AFAIK, they are both same same.... 1Malaysia mah....
This is the loophole ppl are exploiting due to the lower rate for East Malaysian roadtax... It's a loophole but still legal...
Like I mentioned, from what I gathered, during roadtax renewal, the official in charge is the one who verified that the vehicle is physically in East Malaysia... but true to the Malaysia Boleh spirit, he just close 1 eye and approve it.. of course, this 'service' comes with a fee which is only worth the trouble for high cc cars... otherwise, don't bother....
Not sure what would be the implication if someone is caught and can't prove that the car was in EM when renewing the road tax. Then again, with another 'fee', documents can be produced to show that the vehicle was shipped over during that time.. hahaha.... all's well ends well.....