That may be so, but there weren't even 30 F1 cars in 1994 or 5.
In 1994, for example, at the Brazilian GP, there was 26 cars on the grid, and 2 non-qualifiers Roland Ratzenberger and Paul Belmondo.
In 1995, at the first race (also Interlagos) there were 26 cars, all of which qualified. Pierluigi Martini didn't make the start though (not sure why).
I don't think you'll find there was a 30 car grid since at least the mid 80's, possibly earlier.