i've done the skippy 3 day race school on the mx5 cup cars.... i sent an email inquiring on doing a lapping day in the cars. got a call from skippy trying to steer me into the 2 day advanced racing school "as the next step".... i had thought the 3 day school qualified you for "just" lapping..... just being upsold ?
I've done all of the above, the two day course is better than the 3 day..I did it twice. Yes it's an up-sell, but it's not a shake down if that's what you're wondering.
btw...you can do even better still, there are smaller firms that operate out of regional tracks that would be happy for your business. You might want to also consider getting into a shifter cart, those things are WAY faster than you think, excellent way to get faster and you can't buy more speed per dollar.
2 day MX5 experience was well worth it, did it at both RA and VIR and got lots out of it. They will help you with good feedback etc and then my advice would be to move onto a coach/traqmate or both. Todd Lamb lives in Atlanta and he is a fantastic coach for miata/mx5 with very reasonable rates.
I do lapping in the open wheels. While the 2-day will cover some of the same stuff you already did in the 3-day, in total, you'll still get more free lapping per $ than the equivalent number of pure lapping sessions. So, for an "upsell," it's not a bad deal.