The slow speeds are controlled by a clockwork escapement, not travel times. In Leica M cameras it's inside the camera at the bottom. Cleaning and relube is the correct answer.

Since you've got the other camera apart you should have a clear view of the offending assembly. Naptha or liquid lighter fluid to clean it and watch oil for lubrication. The oil should be crystal clear, If it has a color to it, it's too heavy.

the pivots of the gears and pallet are what need the attention. A pinpoint oiler will apply too much lube, Use the oiler and transfer a small drop to a sewing needle or straight pin and apply it by touching the pin to the pivot.