I'd bet the reason I didn't was because of how I had to check them. There were two improvements made between the former and the latter tests.
1) Reversed test leads. The former time, I was juggling + and - in my head. The manual said to put + on X and - on Y; because the manual had it backwards, I'd put + on Y and - on X and compare the result to what the manual said. The latter time, I put the red lead in the - socket and vice versa, which let me connect the leads according to the manual and compare the result to the chart without having to think. KISS principle.
2) Better test leads. The former time I was using probe tips; the latter time, I'd found my old set of alligator clip leads, which made a better connection that I didn't have to think about maintaining while checking the result against the manual.
The test leads--I found that set while cleaning out the SteriLite 4-drawer storage thingy next to my desk. I don't recall what Mom used it for, but I use it for storing the computer things. I cleaned it out a couple weeks ago, and that set of alligator clip test leads was in there, to my surprise.
Of course, it also helps that my bench was clean, too.