Perhaps the best thing to do here would be just to do the flights - then find out whats happens afterwards? Oh and let us know!
Seriously - I think you're trying to push your luck.
Secondly - Don't buy a 'cheap R22' to hour build on - it might bite you in the backside by the time you've had it for a year, paid for the annual, struggled to sell it, fuelled it, paid for the 50hr service, paid for the insurance, paid for the unscheduled maintenance, paid for hangarage etc. Damage limitation - pay by the hour.
Of course the definition of flight time is 'rotor start' to 'rotor stop' so if you're paying on the Datcon which only works on the lever (such as an R44) you can do quite nicely out of shorter 'airborne' flights and not bothering to slow the rotors quickly with the rotor brake... 0.3 Datcon can quite easily be 0.5 - 0.6 rotors turning. The Bell 47 is another great ship for this as the blades spin for ages and there is often no rotor brake!