I know one of UK's intents sewing the underpleats was to save ironing.

I don't iron my UKs. Hang them dry but also use those weighted clamps (hanger clip with two 1/2 ounce fishing weights duct taped to it) on each seam to "pull" the seam while it dries.

Guessing, if I did try removing the underpleat seams all I'd have to do when I hung the kilt to dry would be to put the weight where I'd iron the seam and let the seams dry that way....same as now only having to take a bit more time to insure the underseam fold.

Ron