Drive level for the 32kHz crystal too high?

[Quax64]

The drive level of the nRF51822 is specified as 1µW, whereas the EPSON crystal suggested in the BOM for the EK boards PCA10000 and PCA10001 is specified for just 0.5µW (with 1µW being mentioned in brackets plus a note saying "Please contact us if you require 1.0µW max."). Apparently, a too high drive level can affect crystal accuracy, so I wonder whether I should look for a different crystal. I also noticed that NORDIC suggests the crystal version which is optimized for 9pF load capacitors but, according to the schematics, uses 12pF. Is this somehow related, that is, could it be that the crystal can cope with 1µW but higher load capacitors have to be used to compensate for the frequency shift that might be caused by high drive level?

[testy]

Why not 9pF but 12pF?

Because:

[Quax64]

Thanks, testy, for the clarification. I had a wrong notion of what "load capacitance" refers to and missed to read chapter 3.6.2 of the PS. So load capacitance is rather spot on, which puts me back to square one with my load level question.