What are the best practices to lower the forced cache flushes?

Before, we are seeing the forced cache flushes on certain luns to be in the ranges of 19,088,094. That data is gathered a month ago.

Today, we make the changes to high/low watermark from 80/60 to 60/40 and set the cache page size to 4k.

After the changes have been made, we check the CX again, and see that the forced cache flushes numbers increase significantly. Does that mean our new settings are incorrect?

The intend of the changes is to lower the forced cache flushes and thus improve overall system performance.

Thanks.