3.5 Craft Homunculus help

[DragonsAion]

I'm looking to build an Iron Defender for my artificer and I have noticed something odd. I've listed the basic crafting formula below to help with my question.

cost to craft(gp): market price / 2
cost to craft(xp): market price / 25
time to craft(in days): market price / 1,000

so to make a Iron Defender the formula should work out like this:

cost to craft(gp): market price / 2
-market price not given as it's never sold, however since the cost to create(1,250gp) is given then we can work it out to be 2,500gp.

cost to craft(xp): market price / 25
-the book lists the XP cost as 93xp

time to craft(in days): market price / 1,000
- since the market price was worked to be 2,500, then should take 3 days to create.

So my question is why does it cost 93XP to create the Iron Defender?

93 x 25 = 2,325 not 2500. shouldn't the XP cost be 100 instead? 2,500 / 25 = 100.

is there something that I am missing?

[DragonsAion]

*bump 1 of 3*

[Segev]

Are there expensive components listed that would amount to 175 gp? Those aren't factored into xp cost (nor halved when halving market price to get craft cost).

Alternatively, it's just a quirk of a weird construct that has a lot of odd design choices in its build costs and benefits.