Norminn,

I think she said she had a 31 by 9 ceiling so she'll need enough ceiling
paint to cover 279 sq. ft. In a room with 8 ft of height she has 640 sq ft
of walls to paint. Look like you forgot to paint the ceiling.
I think she should pick her color for the walls and tint the wall primer
appropriately. I presume ceiling will be white so prime that in white. I
don't believe that more than one coat of primer is necessary or recommended
by paint manufacturers. You're correct that the choice of primer and paint
should be complementary (oil with oil or latex with latex).

Dave M.