Correct way of logging hours?

[FL028]

Thanks for answer guys

Lets say I take a flight this afternoon and I hit 0.5 on the tachometer

I takeoff at 1600 and land again at 1630. This is what I put in the aircraft logbook.

But can I then legally put some "extra" taxi/run up time in my own Pilot logbook? Lets say the block time I write in my logbook is 1550 to 1640. Can I do this without any problems eventhough my block time does not match the tach?

Thanks in advance