Why your distances are off and a simple fix.

I finally had time and energy to do a full session and test how much having the R10 misaligned affects shots. Here are my results.

I hit 7 irons as it's my most consistent club.

Baseline setup was the R10 centered, raised up to level of hitting mat and leveled both ways as well.

I hit 10 shots, Launch angle varied 16 to 17 degrees. Carry 190-198. (Mishits were removed). Every shot was a draw which is expected for me.

I then put the R10 on the floor below the hitting mat. Launch angle dropped about 1.5 degrees on average which took about 8-10 yards off the carry. Still only draws, everything else consistent. (This would also make shorter irons go further as it would deloft let's say a pitching wedge, but the longer the iron gets, the more it's likely to shorten carry distance)

I then un-leveled it so one side was higher than the other. All my shots became fades, regardless how hard I tried to draw it. Leveling it the other way everything became a hard hook. It also missed picking up spin on some of these shots.

I then leveled it but had it pointed either too far left or right. This affected the swing path results but nothing else. Curvature, Launch angle and spin were consistent. 

Lastly I hit some drivers. Numbers were spot on when fully aligned. I'm a bit shorter in my garage until I completely trust swinging in the smaller space, but I have had this happen on all simulators I've used.

In summation. Use a level and tape off your center lines. Make sure your R10 doesn't sit below or above the mat. Your numbers will be accurate.