Why not 9.49%?

Due to poverty, I have bought very little in the way of taxable goods over the last week. Yesterday, however, I bought a couple of $1 items at dollar stores. With the tax increase, I had to pay 10 cents tax instead of 8. So, now this 1.5 cent per dollar increase is in reality a 2 cent per dollar increase. Of course, at $2, the tax is 19 cents or a 3 cent increase and for $10 it is 15 cents. If the tax were just short of 9.5%, those $1 purchases would go down to 9 cents.

Something occurred to me at this point. Why isn't the tax just a bit lower so that rounding down would come into play instead of rounding up? I can't imagine that a number like 9.75 is much easier to calculate than, say 9.49. Most stores have registers that do tax automatically. If they don't, calculators are cheap enough. The classic 8.25% tax tended to round down. A $1 purchase had 8 cents of tax, not 9. Of course, lowering the tax by 0.26% would lower the revenue. Of course it would be lowered by about $5 million, when the projection is $30 million to overcome a Medicaid shortfall of $10 million. I think the county can afford it.