I think it's all additive.
i.e.
Let say the power meter's speed can be rated from 1 (fastest) to 100 (slowest)
If I have a starter ball at 0 (meter speed) and a 3 meter club =
my power meter moves at '30' (moderately fast)
---
If I have a proshop ball at 3 (meter speed) and a 2 meter club =
my power meter moves at '50' (moderate)
----
If I have a proshop ball at 4 (meter speed) and a 4 meter club =
my power meter moves at '80' (slow)
But I'm just presuming.