Products in Stock: Order Strategies

Not sure if this is a problem, a flawed design, or simply an annoyance to me.
The Default Requested Quality option is limited to a Q of 300, even though I can manually order products at Q 330.

That is somewhat of a safety feature. There is more to consider about product quality than most players know. Honestly there are few products that really shine beyond 300 quality and I simply order those manually.

I'm mostly wanting it for weapons and ammo.
Most everything I order for consumption is usually at 120Q. But I prefer to buy high Q for most military stuff.

Right. That's the stuff you typically want to order manually though. If you are small, you only need to purchase specifically what you need and as you get large you typically have the flexibility to look for or wait for deals. Either way, it is my impression that the automatic ordering of ammo and, particularly, weapons is fairly rare.