[S.S.]

I've heard of runners getting imbalances from running against traffic, since some roads have a drainage ditch and the left leg would be lower than the right leg. Most ultramarathons that are timed events around a track will switch directions every 3 hours or so to prevent one leg from getting overly fatigued.

If you're only doing one ascent a couple times per week, I don't think it's anything to worry about. If you're doing 10+ miles of stair running per week, then I'd say yes, but it doesn't sound like you are.