I’m not sure how much higher math you’d really need to answer the question “how many tanks has the other side produced?” if these were the serial numbers of the captured tanks:

[689, 341, 386, 741, 982, 414, 845, 241, 180, 447, 880, 21, 583, 993, 812]

it’s tough to see an argument for anything other than: a. about 1,000, or b. 1,000ish but there may be a confounding fact pattern we are unaware of....