Remember that your new pads are thicker than the worn ones...so the pistons have been recessed a bit to accommodate the extra width, thus pushing the excess fluid back to the reservoir.

There isn't much fluid volume available between MAX and the top of the cap. Leaving the fluid level as is probably wouldn't hurt, but I always believe engineers have a reason for marking things the way they do...

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car