Converting Saudi Driving license to Oman

A lot of websites says about conversion of GCC driving license to oman driving license.
But from experience, we cant convert or exchange all GCC country license to oman.

I had a Saudi Driving license. But when I got a new job in oman and tried to exchange with the Oman driving license, I was alarmed to know that, having a saudi driving license is of no use. I have to undergo all test ( Slope test, Drum test and Road Test ). Which is similar to to taking a new license.

But since I had indian driving license, I dont have to take Slope and Drum Test.