strange one. the actual maths = $260,442,000 so it'll have to be rounding errors. how rounding errors occur on an item that has to be put for sale at a unit price..? ok, I've an idea... here's a theory:

the person selling has to put it for sale at unit price for set units (150,000 tanks for $490), and there can't be rounding errors in whole numbers.

the only slightly complicated item is the tax @ 1.06, so it's likely to be in the way the tax is calculated/added.

in fact, it seems to me tax is added twice.. the person selling is charged tax on sales, and the person buying is charged tax on market purchases...

this introduces far more decimals (therefore more rounding) than addition of sales tax once would do.

so my guess is it is the double addition of tax that is causing the rounding errors, and the difference in cost.

to elaborate, if one person is selling as a commie (@ 1.1) and one person is selling as a rep (@ 1.06) then the final cost calculation could feasibly be rounded differently...

costing you the princely sum of 1$.