Handbook of ROCOR Liturgical Practice:

How is the Proskomedia to be concluded when served for a Hierarchical Liturgy?

In the ROCOR Synodal practice, the Priest (and Deacon) serving the Proskomedia prior to a Hierarchical Divine Liturgy, fully complete the Proskomedia in the normal way — including saying all the prayers of covering the gifts, veiling them, and censing, precisely as is done when serving without a Bishop.

In some other traditions, the Proskomedia is left unfinished prior to a Hierarchical Liturgy; or if the gifts are covered for practical reasons, this is done without the prayers of the covering being said, in anticipation of the Bishop reading these later when he completes his commemorations immediately before the Great Entrance. However, in our tradition we do not practice this; the Proskomedia is fully completed before the Liturgy, and when the gifts are uncovered for the Bishop for his commemorations, he re-covers them without repeating the covering prayers that have already been said by the Priest.