Ah, I finally found where I heard it from… It wasn’t on Catholic Answers like I thought (my mind is going ) however on EWTN in their Library on Liturgies…
Is it acceptable for the priest to say one prayer over the bread and wine, combining the two prayers?
A Dominican priest from Charlottesville, Virginia, has kindly pointed out that the celebrant who used the single prayer may have been a member of the Order of Preachers.
He writes: "In the Dominican Rite Low Mass the chalice was prepared before Mass and the oblation was made with a single prayer and single raising in both the Solemn and Low Masses. At Solemn High Mass the chalice was prepared during the Gradual.
"Both of these practices were also found in the liturgical family embracing the local uses of northern France and the Sarum Rite in England, from which family the Dominican Rite evolved.
“It is not uncommon for some Dominicans to use the old single oblation and to prepare the chalice ahead. The motive is nostalgia, not haste.”
The priest adds that, while he harbors much affection for the Dominican rite, he himself never follows this practice since it is contrary to the spirit and rubrics of the Roman rite.
I believe that his is a prudent decision when celebrating Mass for a congregation. Otherwise, the faithful may be confused by the difference in rites.
As your Pastor isn’t a Dominican then I can’t really think of any reason why he would do this.