It certainly seems like they weren't consistent.
It also look like the greater version only appears in UE? If that's the case, I'm not overly surprised that an item from the CRB wasn't consulted thoroughly before making the new one.
What other items offer similar abilities?
Spell Storing is all that's coming to my mind. But (Spell level)^2 *2k is way too much for what the shield does. I'm not sure how to finagle the mathematics though.
Mimicking the weapon enchant is another way to go, but figuring it as a +1(or more) bonus also seems a bit steep.
What it does:
A single spell (up to X level)
using spell completion (must provide M/F/DF at time of casting)
scribed at half price (presumably for the reusable scroll?)
Possible methods
1. only spell level -> (2000 / 3^2) * 5^2 = 5556
2. scroll cost -> 375 *5 = 1875 ~=2000 -> 1125 *5 = 5625 (x5 can be viewed as "scribe cost x10" to represent reuse)
3. spell level * caster level -> (2000 / 3*5) * 5*9 = 6000
4. some mix of everything -> 3^2 *200 + 1/2(375) = 1988 ~= 2000 -> 5^2 *200 + 1/2(1125) = 5563
Alternatively, say it's a "fixed cost" for the half price scribing, then figure in the price of a scroll in some multiple.
5. 375 + 1625 -> 1125 + 1625 = 2750
6. 750 + 1250 -> 2250 + 1250 = 3500
etc
I suppose fractional calculations are also available. If you peg the fixed cost at 1500, a 5th level version would be 3000.
My opinion is that it's one of the squared formulas. Likely, you could get away with (spell level)^2 *200. (I suspect this is where the greater's "1000" comes from, they forgot the squared element. Additionally, it puts the standard version at 1800, which is very close to 2000.) Otherwise, pick your favorite or offer some different math.
