I just took another look at your original question and I think I have some bad news for you. You are looking to increase from 100 GRT to 200 GRT and you assumed that the rules in 46 CFR 11.422 applied:
(a) Each national endorsement as master or mate of vessels of less than 200 GRT is issued with a tonnage limitation based on the applicant’s qualifying experience. The tonnage limitation will be issued at the 25, 50, 100, or 200 GRT level. The endorsement will be limited to the maximum GRT on which at least 25 percent of the required experience was obtained, or 150 percent of the maximum GRT on which at least 50 percent of the service was obtained, whichever is higher. Limitations are as stated above, using the next higher figure when an intermediate tonnage is calculated. If more than 75 percent of the qualifying experience is obtained on vessels of 5 GRT or less, the MMC will automatically be limited to vessels of less than 25 GRT.
(b) The tonnage limitation may be raised as follows:
(1) For an endorsement as mate, with at least 45 days of additional service on deck of a vessel in the highest tonnage increment authorized by the officer endorsement.
(2) For an endorsement as master, with at least 90 days of additional service on deck of a vessel in the highest tonnage increment authorized by the master endorsement.
(3) With additional service, which, when combined with all previously accumulated service, will qualify the applicant for a higher tonnage officer endorsement under the basic formula specified in paragraph (a) of this section.
(4) With 6 months additional service in the deck department on vessels within the highest tonnage increment on the officer’s license or MMC endorsement. In this case, the tonnage limitation may be raised one increment.
Unfortunately, I believe that USCG considers the initial 100 GRT license as a completely separate endorsement than the 200 GRT license. The rules under 11.422 only apply if you receive a tonnage restriction on your 200 GRT license. For example, all hawsepipers generally start out with a 100 GRT license (it may be restricted to 25 or 50 GRT, but we’ll still call it a 100 GRT license). This is because it isn’t even possible to apply for a 200 GRT license (which also may be restricted to 25, 50, or 100 GRT) unless you have 180 days service as Master or Mate. Once you get your 100 GRT license and obtain another 180 days service as master or mate, you can again apply for a new 200 GRT license. But the upgrade rules of 11.422 don’t apply, as USCG sees the 200 GRT license as distinct from the 100 GRT license. It is even likely that when they issue you a 200 GRT licenses, it may be restricted in tonnage to 100 GRT or less).