Sure - the first part of the thread i linked above is about New Dose Wonkiness. Some cats react to an increased dose with higher numbers, too. That may be what you are seeing. Increasing him from 2.25 to 3.0 is really too big of an increase. The very most we increase a dose of a cat that isn't a high dose cat would be 0.5u. You can't rush a cat to regulation. Increasing by too large of an increment can make you overshoot the "right" dose for him - and a cat that is overdosed can also have high numbers.
If I were you, I'd drop back to 2.75 with tomorrow morning's shot.
Probably nothing wrong with the vet tech's shot - more likely it's the NDW or bouncing.