Contrast can appear lower in larger prints inspected closely, which can fool you. Printing a step-wedge will prove that the contrast doesn't really change unless your enlarger is a bit dim and you get into reciprocity failure of the larger paper.
Using an enlarger meter will allow you to adjust the exposure correctly for the change in enlarger height and obtain a tonally equal print... but you might still want to bump the contrast anyway, i.e. deliberately interpret the prints differently at different sizes. I've been leaving it alone.
I buy identical papers in both 8x10 and 16x20, do my test-strips and dodge/burn experiments at 8x10. I know for a couple of pairs of enlarger heights what the exposure bump required is so that once I have the 8x10 down, I can go straight to the larger paper with no further testing or wastage.