ok ill make this as simple as possible.

A SAFC cannot conrtol VTEC. it can only control fuel.
A Fields VTEC CONTROLLER is an older styl VTEC controller. this allows you to tune fuel AND set Vtec engagement.

Now, lowering VTEC really wont do anything UNLESS its on a dyno. itll feel sluggish and slow likewiese if you set it to high . a/f ration is relevant to when the VTEC cam switches on from the LOW cam AKA NON VTEC lobes on the camshaft.

If you are changing vtec to be lower, you SHOULD hear it crossover, but your right, it might be dog rich or slow and sluggish and not take off until the "stock RPM" that vtec was orignally set at.

Unless you have a $700 header and big camshafts, you cant set vtec really low IMO. you cant move enough air.

FYI: skunk2 Stage 1s like vtec around 5500-6000rpms. they are a little more aggressive than CTR camshafts which engage at 5800rpms.

My vtec engages at 6800 on my new engine, but i also rev to 11k.

Vtec really shouldnt be touched unless you are on a dyno. and no, ANYONE with a dyno (MAINSTREAM PERFORMANCE , Batlground, Knowledge etc ) can tune a SAFC and a Fields.

I would personally sell the SAFC 2 and the Fields controller and buy a VAFC 2. VAFC can do the same thing that a SAFC AND a FIELDS can do and it would eliminate ALOT of wiring. of course them i would tell you to go UBERDATA cause its cheaper and then you can crontol ignition