I do not have to load the flights twice in v4.6 (nor in the 767 v1.5). I'm happy with the 757 v4.6.

Do this with the 757 v4.4. Go to FSX\SimObjects\Airplanes and highlight your CS_B757-200, CS_B757-200F & CS_B757-300 and ZIP them. If things are not good with v4.6, reinstall v4.4, then unzip the above, overwriting everything and you will be back where you are now. This might not be able to be done with the McPhat WA liveries, but I don't know how they work with the CS757 because I don't have any of the them.

Mark