If you plan to keep your 103" displacement, I think the builder is trying to take you for a ride. Not a damn thing wrong with the SE cast flat tops, for what you're doing. If you really want your bike to come alive, for what you'd spend on the SE Pro heads, you could send your own heads to a reputable head porter, who can tailor your heads to a specific cam.
Are the heads on your bike bone stock? 168psi seems a little on the low side, for an early closing cam like the 255. Compression releases maybe not disabled? Throttle butterfly held wide open?
2009 Vivid Black FLTR/120R/Dewey's headwork/TMan 625G/Fuel Moto XXX 2/1/2 w/4" mufflers/HPI 55