That 1/4 inch slope is basically a rite of passage for anyone who's ever worked on an old house. Spent a full weekend once shaving a cabinet door before realizing the floor dropped 3/8 inch across the room. You learn real quick that level means nothing in these old places, just gotta measure from the ground up.

Wait, so @the_sean is saying sweating is worse than crying now?

Oh man, zeroing it out is key! I've seen guys panic over a false reading too, nothing worse than that heart drop when you think you soaked up a month's worth in one spot. Now I just tap the screen quick before I cross the threshold and it saves so much headache.