so many arrows

I am just wondering why there are three different types of regular arrows available.

The ranger gets 3 ammo 2 weight arrows in their starting gear.
The thief gets 5 ammo 1 weight arrows in their starting gear.
You can buy arrows that are 3 ammo 1 weight.

Is there a reason that thieves start with far superior arrows then rangers?  Can you buy more "thief arrows", or once you exhaust your starting arrows you are stuck with regular ones?

Also the Rangers extra heavy arrows means it's almost impossible to start the game not overloaded.

It seems overly overcomplicated to have 2 class specific types of arrows, one of which is far superior.

I think the intention is too have the 'arrows' specific to the bow? Where you just take on the tags of the bow?
The Ranger has a Hunter's bow (and Hunter's arrows) whilst the Thief has a Ragged bow (and Ragged Arrows).

That said, I think you have correctly pointed out a typo? In previous iterations where load was determined differently and gear was bought individually at Chargen, arrows were of two types:
Bundle of Arrows 3 Ammo,  2 Gold, 1 Weight
Elven Arrows 4 Ammo,  20 Gold, 1 Weight

I still use this paradigm. Ye olde standard arrows are as listed in gear: 3 ammo, 1 weight. If you are an elf ranger you get the elfy arrows instead :)

I like the old arrows better!

I suspect it may be an editing issue? I would expect all arrow-ammo to conform to a specific format.