Ayaw ko na ng paulit ulit na pagsasabi kung bakit puwede o hindi puwede ang isang kanta sa isang part ng misa.
The link below will give you a link to the draft of the Diocesan Guidelines for Music in the Liturgy. The first part (Proemium) is the premises on which the rest of the guidelines are founded. It was written in a scholarly manner with solid foundations on the theological, historical and pastoral aspects of the liturgy and music in the liturgy.
Once signed by the bishop, it will be the rules. When you sing in the liturgy, you just don't sing in the liturgy, you should sing the liturgy. Hindi ito parang variety show na kung anong maisip ng musical director e yun na. There's always a right and wrong way of doing anything.