Reset price to include cost increase from margin percentage

[Shopping bear]

To factor in cost recovery I have the old margin and the new margin. Do I take the new margin minus the old margin to use that for the lost margin to include in the price or instead do I take the new margin minus old margin divided by new margin. The second way gives a higher number than the first way but since it’s a percent already isn’t it just the new margin minus the old margin??? So like if the new margin is 43.21% and old was 46.37% that’s a -3.16% to put back into the price. But if I do =(new margin 43.21% - old margin 46.37%)/new margin 43.21% that equals -7.31%. But which is the right way to do it? My guess is the first way of new minus old margin but I’m not sure.
The price to base this on is $177.14
Using new margin minus old margin is -3.16%
result would be to do =round(177.14*(1+abs(-3.16%)),2) which is $182.74

Or using this of new margin-old margin divided by new margin comes to 190.10
=round(177.14*(1+abs(-7.31%)),2) which is $190.10

which is the right way?