A couple of times now I've been told to climb to an altitude above my planned level. Last night it was 6000 against my submitted 4000 feet. But when I started to get above 4000 feet I was told off for busting my altitude, erm hello Control but you told me to climb....

I have not used it for flying that low but here are some considerations:First, on the controller page, don't forget the cruise is in FL format (or thousands feet divided by 100 such as 40 is 4,000).I would check your departure and arrival MSAs on the controller page.Make sure your altitude on each leg is above the MSA designated for that portion. RC measures in quite of bit of the surrounding area and perhaps at that low a cruise level it somehow is getting things confused in trying to maintain a safe altitude over terrain.

and if you are flying outside the untied states, make sure you know what the transition altitude and transition level are, and set your altimeter accordinglyjd