Dish elevation

First of all, please excuse my ignorance...

About a year or so ago I installed my own motorised dish. I was never able to get it properly on the arc. For satellites furthest west I would need to tip the dish elevation down a few degrees and for satellites furthest east I would need to tip the dish elevation up a few degrees.

Doesn't seem to make sense at all.

I don't want to have to take it all down and start again and I had enough of a nightmare last time, hence why I just gave up and...

Dish elevation