Mining amps are capped for a while now.
This means like with amp 2 you can get max a claim 14-15 so no longer is a higher claim/tower possible.
For amp 5 I think it was a 24-25 claim (not sure about that) need to ask some friend miners)
Imo this is done to mining because its more fair and I like it this way.
The higher the amp (as from lvl 3) the higher the risk of loosing but also the higher % of getting a biggy.
Question is will that biggy pay off all the losses you had in the past
In my opinion NO and that's what the past have teached many of us unless you are extremely lucky