AT 440MLa Cartridge Adjustments - Why did this work?

I had bought this cartridge a long time ago and did not like it immediately.  Even with good alignment it produced a thin sound with a lot of high end, poor mid and little bass.  I’d read a little at the time and people recommended this cart needed a lot of break in time.  I just decided to put it aside and use other carts.  Well I was reorganizing the other day, found this cart and decided to give it another try.  Upon initial install, I found the same problem as before.  But I decided to tinker a bit.  I began by adjusting the VTA by increasing the height of the tail of the tone-arm.  Better.  Then I increased the VTF from 1.4g (recommended in user manual) to 1.6g.  Still better.  And finally I added 5db, then 10db of gain by adjusting my Hegel V10 phone stage dip switches.  The thing sounds great now!  Clear, crisp highs, solid mid-range and well-defined bass.  Still with no meaningful break in time.  Perhaps it will only get better as it breaks in.  So my question, is why would the changes I made improve the performance from a thin, poor sounding cart to something that is really producing a beautiful, full and defined sound?  I’m asking for the science/physics answer.