Hunter's Hat Issues

Hi, there is some strangeness with the Hunter’s Hat item.

The soft cap on ranged damage is equivalent to using materials above 2.45 in value, multiplied by 3.6 (or 3.45 with the +1). This is seemingly the case for guns, for example.

The Hunter’s Hat has 5 base ranged damage, or 500%.

The formula listed is strange. I made one with +0.3 ranged damage from materials, and it listed the following:

Subtotal +1 = 1.3

Base = 5

Quality x1

Result = 6.5

Where is the extra 0.2 coming from in the result? It wasn't listed on the item (it said 530%, not 550%).

Then, when I upgraded the Hat to Uncommon, it incurred instability as follows:

Subtotal +1 = 1.3

Base = 5

Quality x1.8

Result = 11.7

As you can see, the extra 0.2 is still being counted for the result, this time listed on the item.

Instability = -5.31

Result = 6.39 (listed on the item correctly this time as 639%).

Isn't it also getting instability earlier than other ranged items? A gun can have 3.45 x 3.6 = 12.42 before getting instability. But this hat is getting it at 11.7 (as if a gun were at 3.25 x3.6)

When upgraded to the next level, it hits the hard cap for ranged damage of 650%.

So there is an extra 0.2 being added, displayed in the formula at common level and displayed in both the formula and item stats at uncommon level.

Secondly, the instability calculation for this item is seemingly different from other items.

Thirdly, is an item that will hit its hard cap just from being upgraded a good design decision? Would it make more sense if it were 0.5 instead of 5 base Ranged Damage?

Thanks!