I recently noticed my 60 backseat is much harder to fold up than the 40. Feels like I have to pull it up and while pushing the seat firmly back, pull the underwear lever down to hold it in place.

Is this normal?

 

No, other then the extra weight of the seat, it should be the same. There maybe something stuck in the mechanism, or needs lubrication

 

I'd check to make sure something hasn't become lodged in the mechanism, or try some lube like previously mentioned.

 

Just to be clear... yes, you DO have to push the lever (seat "leg") down to hold the seat in place.

The weight of the seat makes it naturally fall down (from the "tall mode"), unless the lever is locked in. True for both sides.

If either stays up without the lever locking in... well, that can also be an issue.