Hi again todorovia, yes I have X at the end of 13d to give the expression in full. It seems pretty pointless multiplying a number using 1 (the multiplicative Identity) and the down number 1s only appear in crossing cells with the only numbers appearing in the grid being 101 & 5 which obviously has to be squared to give 2525.
I don't submit puzzles so it doesn't really affect me and I was only trying to give guidance.