Product number relation to HuCard size... sometimes?

[Psycho Nulltard]

Disclaimer: Yes, I searched the forums/google. No, I didn't find my answer despite knowing with certainty that it exists somewhere on these forums already. Sorry. ):

So I was looking at the Product # printed on the back of turbochip boxes and noticed that the first two numerals of NEC/TTI distributed titles seem to relate to the size of the card in megabits.  However, when checked against actual ROM size there are a couple of exceptions to the rule...

Ballistix TGX030059 is only 2 Mb
Timeball TGX020034 is only 1 Mb

Does anyone know why this is?  Did NEC/TTI put these on larger HuCards than required because they had excess inventory?  Did a mischievous deity plant these four product numbers in the TG lineup just to mess with my mind decades later?  Does anyone else care/wonder why these two excellent titles don't match up???