What was your routing? If the segments were over 2,000 miles (e.g. LHR-DOH) then you should still get 35 TPs on a basic economy ticket.

I don't think this has anything to do with changes from 28 April. It sounds like there might have just been an error.

Also, based on my experience, bear in mind that BA won't stand by what the calculator shows, "the total we show you is a guide and I’m afraid we cannot guarantee you will earn this amount" is what they told me.