That's the standard offer to leave a SERO (and other legacy) plan, unforuntately I haven't heard of anyone managing to avoid the $10 EVO fee. With the EVO as popular as it is with the fee, Sprint doesn't seem to have any real incentive to waive it.
I wonder if folks would be more upset if Sprint had just charged $450 for the phone, like they did with the TP2?
They were a bit more generous a few months back, I managed to snag $20 a month as my bribe for leaving SERO and trading in my Mogul for the Moment. (I love the Moment, just gonna love the EVO more

)
The monthly credit DOES STACK with other discounts including EPRP and Employer based.
I made a post earlier listing the easy to get public discounts:
10% if you belong to a credit union
15% for students
15% Everything Plus Referral Program
All are publicly available and easy to get.