It sounds as though they operate a "first past the post" system in Verbal reasoning, so your child would qualify if he/she is in the top performing 100 students, but must also show reasonable ability (hence the 50%) in Maths and English.
The governors of each foundation school set their own selective criteria. The LEAs in selective areas set the criteria for maintained schools in their area as I understand it. I'm not in Torbay so I don't know their system.
I'm in East Devon and the grammar my child is hoping to go to ( 2 days till we find out
) sets a "qualifying level" (no idea what the level is though!) and all children above this are then assessed for distance from school etc.
I suppose your system favours the higher performing children however far they live from school and our system favours any just passing living near the school. As usual, some win, some lose!