500 grt to 1600 grt sea time requirements?

Hi All,
I have been told from multiple sources, some from the maritime school I took classes at that you only need a year of sea time on vessels over 100 grt to upgrade from 500 grt to 1600 grt. There is nothing in the cfr’s under sea service for 1600 grt master regarding increase in tonnage from 500 grt.

I guess man, if you look at the checklist and do the math…1440 days req’d for the 1600. 1080 days which is req’d for the 500 gives you 360 days needed. So I would suppose you just submit the paperwork if your current ticket is valid, and you’ll be good to go.

Half the time for the 1600 needs to be over 100 tons. That is two years over 100 tons…

That’s what isn’t clear. I didn’t have any time over 100 tons that was used towards my 500 ton 2 years ago. That’s why I’m wondering about there being a special upgrade for people who have a 500 and were sailing on it

If you had no time over 100 before your 500 ton then you need to have been on vessels over 100 tons since then (the past two years).