Here is a document issued by His Excellency Most Reverend Robert H. Brom, Bishop of San Diego, to the priests of that warm and sunny diocese. It came with a very short cover letter and a summary of the Motu Proprio Summorum Pontificum.
Take careful notice of the title of the following document. Emphases (except in the titles) and comments are mine.
APPLICATION TO THE DIOCESE OF SAN DIEGO
According to the Apostolic Letter, Summorum Pontificum, priests are authorized to use the Roman Missal of 1962 in the celebration of Masses without the people on any day except in the Sacred Triduum (art. 2). The faithful who spontaneously request it may be admitted to these private celebrations (art. 4).
Notwithstanding this authorization, priests should not attempt celebrating Mass according to the Roman Missal of 1962 without competence as regards both the rubrics involved and the Latin language required (cf. the cover letter of Pope Benedict to his Apostolic Letter). [It seems to me that some priests might read this and take it to mean that they need to know Latin well. That is NOT what Summorum Pontificum says.]
They may do so in churches and chapels only with the permission of the appropriate authority, and may not advertise these private celebrations. [So, His Excellency is saying that these Masses must be.... secret?]
Religious communities may have celebrations of Mass according to the Roman Missal of 1962 as authorized by the Apostolic Letter (art. 3).
Pastors and Parishes
In any parish, a stable group of parishioners [This is NOT what the Motu Proprio says. First, this is based on a mistranslation. The Latin does not say "a stable group". The Latin says that there must be a coetus, which can mean as few as 3 people (and can include the priest himself!) and they must be present consistently, or continuously. "continenter exsistit"] who are attached to the older form of the Roman Rite may request the celebration of Mass according to the Roman Missal of 1962 on weekdays or even on Sundays and feasts (art. 5.1 & 5.2).
Pastors may accede to such requests only when they come from their own parishioners [I wonder if this is in keeping with the Motu Proprio. This is an ambiguous point.] and when a compent priest is available to preside. [Notice that no citation of the M.P. is given here.]
Pastors must see to it that the good of these parishioners is harmoniously reconciled with the overall pastoral good of the parish, always avoiding discord and fostering unity (art. 5.1)
Subject to these same conditions, pastors may permit celebrations of Mass according to the Roman Missal of 1962 in particular circumstances such as weddings and funerals (art. 5.3).
As the good of souls may suggest, pastors may grant permission to use the older ritual in administering the Sacraments of Baptism, Matrimony, Penance and the Anointing of the Sick, i.e., Extreme Unction (art. 9.1).
Again, pastors may grant such permission only to their own parishioners, [The "good of souls" suggests a much wider practice. Say, for example, a priest with a hospital or nursing home in the territory of his parish finds non-parishioners requesting the older forms for granny who is dying and wants the older Last Rites? It strikes me that the principle of odiosa restringenda and the "good of souls" suggests a much wider practice.] and when there are celebrants available with rubrical and linguistic competence.
Just as in celebration of Mass according to the Roman Missal of 1962, there may be no intermingling of parts from the new Roman Missal, so in administering the other Sacraments according to an older ritual, there may be no intermingling of parts from the new rituals. [This bishop clearly things that the newer Lectionary cannot be used with the older Mass. I wonder if this means that a community would, today, be forbidden by this bishop to celebrate the feast of St. Maximillian Kolbe, rather than the Vigil of Assumption, as it is in the old calendar?]
Permission of the pastor is required for any other priest to preside at a parochial celebration of Mass according to the Roman missal of 1962 or at a parochial celebration of the other Sacraments according to the older rites.
Permission of the Bishop is needed by any priest who wishes to preside at a celebration of Mass according to the Roman Missal of 1962 or at a celebration of the other Sacraments according to older rites outside of a parish church, for example, in chapels. [Huh? What if the pastor has juridiction in those chapels?]
Permission of the Bishop also is required for individuals or groups of the faithful who desire interparochial or non-parish based celebrations of Mass according to the Roman missal of 1962 or celebration of other Sacraments according to older rites [?? Does this mean that people from other parishes cannot attend the older Mass if celebrated in parish X? Or does it mean that there is going to be, say, a conference and the organizers want to have the older form of Mass, the pastor of the territory cannot make the decision, but rather the bishop?]
Signed: /+ Robert H. Brom
Bishop of San Diego
August 1, 2007
This document strikes me as being just as open to the Motu Proprio as it has to be, but no more. While making references to "the good of souls" it does not seem really seem to consider the possibility of flexibility.