A slight hijack, but related to playfield angle.

I got a digital level from Home Depot. My bubble level next to the ball launcher shows nearly centered, with the bubble a bit toward the launcher but still well between the lines.

I put the digital level on the playfield and it says it's 5.9 or 6.0 degrees tilted (tested it both ways so it's accurately calibrated since it gives almost the same answer). Yet, I have read that 6.5 degrees is what this playfield should be.

So, my question is:

1. Trust the digital level and raise the playfield rear a bit?

2. Trust the bubble level and leave it at 6.0?

I haven't worked out via high school trig how much of a lift to the rear that 0.5 degrees is yet.

Why are these two things in such disagreement? Or, is the bubble level just pretty inaccurate?

Thanks!