yeah vtec controllers are old school.
honestly you only want to change the vtec engagement based on the power curve as shown by a dyno. it should be smooth for the most part with no abrupt change in power. usually you have some sort of modifications to the motor which warrent the lowering of the vtec point. then you would normally want to retune all the maps as well.
chrome, hondata, aem ems, they all do that.