I agree with you that BT is needed to renew or upgrade an MMC.
BT is also required every five years as of the 2010 Manilla Amendments which went into force in 2017. (Actually the requirement is to complete PST, FP&FF, AFF, PSC&RB every five years which we call BT.)
Take me for example. I last took BST in 2015. Therefore my BT needs to be renewed in 2020. I renewed my MMC in 2017 which lists BT. My MMC needs to be renewed in 2022. That shouldn’t mean my BT is also valid threw 2022. Right?
More troubling, I looked threw the digital training records of the crew we get from the office. In most cases the BT date matches the MMC date - including mine showing valid threw 2022 which should be incorrect. This means there is no way for me or the office to know who has a valid BT and who doesn’t without asking everyone to produce their paper certs. This likely means there are several crew aboard without valid BT (we have about ninety crew onboard).
That leads to my question about what happens if the BT is past five years?
(If I’m wrong then so be it. I want to know that I’m not wrong before I escalate this officially.)