No, from the Civil Service point of view, only a change in grade is promotion. What sometimes the HR and boss try to do is to create "fake" promotions to try and retain long serving staff who have maxed out on their grade and try to motivate the youngsters by giving them impression of rapid career progression. That's why have all these sub-grade nonsense.

Sub-grades are fake and not recognized outside of a specific ministry, i.e. you can't claim that you are now a high MX11 from MTI and want to transfer to a low MX10 in MFA. They will tell you to fly kite and say MX11 is MX11, MX10 is MX10. You either qualify to move to MX10 or you don't.

Sub-grades are also not practiced consistently and some ministries have more while others don't have at all.