Gas Turbine -Difficulty Upgrading

Does anyone have an insight as to how the CG evaluates qualifying service on a Gas Turbine powered vessel in regard to upgrading a Steam and Motor engineers license.

I knew a US Navy Gas Turbine Tech that got out and the USCG let him sit for the QMED tests and he was serving as such getting his engine time; his plan was to move up as he increased his seatime/horsepower on engine driven ships.
I have also seen Licenses for example: 1st Assistant Engineer of Gas Turbine, Steam or Motor Vessels… I guess you could get a license that just read “Gas Turbine” but it wouldn’t be much good.

From Marine Safety Manual III
[LEFT]2. [U]Gas Turbine Vessels. [/LEFT]
[/U]A motor license and a steam license both qualify the holder to serve on board gas turbine propelled vessels. No specific endorsement is needed. Service obtained aboard gas turbine propelled vessels may be credited as both motor service or steam service, but can not be credited twice. For example, an applicant for a raise of grade from 3 A/E of Steam and Motor Vessels to 2 A/E of Steam and Motor Vessels has 360 days of gas turbine service. The time may be credited as 120 days towards each mode and 120 days towards satisfying the 360 day requirement