107CH,
Nothing wrong at all with asking questions!
You flux as often as you want, or as often as you think as necessary. There is no such thing as fluxing too much!
The rule is, when you let the melt sit for more than a couple minutes, or you see a visible film or skin on the melt, then you should think about re-fluxing. The NRA Bullet Casting manuals recommend fluxing a minimum of every 15 or 20 minutes, I think.
Bullet alloy constituents (lead, tin, antimony) are different densities, and therefore, they tend to separate when in liquid form. You want the alloy to stay uniform for weight/density/hardness consistency.