If it were up to me I would suddenly jump to movie
in whim just to stop this kind of questions (or make them seem insignificant in comparison) ;-)
There is a general development principle that database-internal numbers should not be exposed in public interface. According to that principle, the URLs referring to movies should be like
/TAS/SMB1byKlmz/v1 rather than
/1330M.html . But the fact is that these numbers are a handy way to refer to individual movies. I would just prefer that people take it as that, a handy way to refer to individual movies, without trying to assign any particular meaning to those numbers; their magnitude or their relative ordering.
Yes, the database assigns the number with a certain algorithm, in a successive sequence, but the numbers may also skip, and have irregular sequences depending on a (small) number of issues.