BruceS:I have reported the bug to Groundspeak. You might try leaving it at W but enter a "-" sign in front of the degrees and see if it sticks
I just tried this trick. It kind of works, but the result is even worse. When I enter e.g. W -7 35.2 then the minutes stay positive, so the result is E 6 24.8. Not really a workaround, sorry.