That's proper 'man maths'!
It's not the same money that's taxed each time! Anything taken from the company will either be salary (potentially liable to the new extra NI) or dividends (which will be subject to the new NI) ... if it's shared between you and Mrs Toadstool it will be 1.5% each on half the amount, so still only 1.5% of the whole amount in total!