Hi, I’m facing unusual situation when auditor asked me why change between 2 years values are so high, however she did via percentage change like below pointing that change = 6.45% between years and is more then 5% (our threshold) and it’s significant in our situation.

I don’t think this is correct, once we already applied ratio and calculation .
Think correct to say that diff = 3.23. Am I right ? Trying to prepare myself to fight of my case.

Just to understand your case.
what do you mean by policy per 1000 members?
Isn't more policies good? why?

Per my understanding, If the measurement is policy/1000 member change in the measurement is from the measurement.
So 1 percent of 50 is 0.5
So the difference in the measurement is +3.23 which is 3.23/50*100 percentages ...+%6.46

Thanks OBH! This is just a general question if you can apply percentage change with this simple formula (3.23/50*100) to the values which already went thru relative (division) calculations (30K/60K*1000).
For this sample higher values per 1000 is better ,but it's not really matters in the context .
My opinion that we CAN NOT use 6.45% in comparison. You apply relative to relative, so it doesn't make too much sense.

One percentage is just the value divided to 100, (1/100 of the value)
So if you can divide by 100 you can use percentages.
You can even take the percentages of percentages.

So you need to read your contract/agreement what is the exact definition.