MSP430FR6989: LFXTDRIVE does not cause any measurable differences in power consumption

Tool/software:

Hi,

in an application using the MSP430FR6989 the LFXTDRIVE was set to 2 (225 nA). However, due to different reasons it should now be changed to LFXTDRIVE = 3 (330 nA).

In order to ensure that everything is fine, the pcb was re qualified by the crystal vendor and here it turned out, that the Drive-Level was almost identical for both settings at around 19nW.

Is that an expected behavior even though the current values are changing?

Additionally, it is not clear as to why the CL,eff is increasing with an higher drive level. Can you help me to understand why that is the case?

Thank you!

Marinus