Just a quick perspective from a total noob who is still working on all aspects of straight razor shaving. I think that the need for multiple passes may trick you into feeling the need for more pressure. What I mean is, you take that first pass and then give the spot you just shaved a quick feel and even though you may have cut some beard and heard the right sounds, the tactile feedback of your touch says "hey - doesn't feel like you did much of anything here!" So, of course, what do you do but try it again with more pressure. I guess it best to focus on "shaving the lather" and then proceed with the next pass without over evaluating how well the first pass did.

With my beard, it seems like if I take another pass in the same direction with more pressure and reevaluate, it seems like that worked better! So you get bad reinforcement of the bad technique. Still working on it all, but perhaps this is some food for thought for some of you. (Please pardon the way my over-analytical anal retentive mind works if this makes no sense to you!)
Jerry