my range rover up shifts at 4000 rpm and down shifts really hard

What is your question?

I've change fluid and filter. It doesn't smell burnt when pan was off everything looked really clean. It shifted better for 3 months after I done that but after I added just a little bit of tranny fluid bc it has a slow leak and went right back to shifting at almost 4000 rpms and is down shifting really hard What else can I do or check without having professional help I've let out the little bit of fluid I added to it thinking i might have overfilled it but it didn't fix it. How does it go from not shifting properly to shift really good for 3 months then right bk to shifting like it was b for changing fluid and filter