It was night on Sunday when he was in the tomb. You have to think like a 1st century Jew.
So when was Saturday night? (If that was actually Friday night - then when was Friday night? Thursday night?)
No matter how you think it - there are only two nights he was in the tomb, not three. The night after he died and the next night. He rose at dawn at the end of the second night. There is no third night.
You can't count the same night as both Saturday night and Sunday night.
I think you are playing semantics here. Use any name or any word you choose - he was still only in the tomb on 2 nights.