Currently, most of the specific armors, shields, weapons, and the rods and staves that act as weapons have COSTs in the lst files that are the whole cost, or most of it, such that resizing for Large or other sizes generates the wrong end cost.
For example, a Frost Brand that costs 54,475 gp has that as its COST, so that a Large one would cost 108,950 instead of 54,525 (54,425 gp + 2 * 50 gp, the cost of a greatsword).
The costs of these items could be adjusted so that the COST is that of the plain item, with MAGIC_COST making up whatever is needed to get to the full regular cost.
For artifacts and other items with zero cost, the lst COST should be zero so that, when doubled it would still be zero, and not a few gp off. (The alternate weapons of the Rod of Lordly Might are examples of this problem.)
(This fix won't work as expected, however, until DATA-1051, "Cost errors in interaction between MAGIC_COST and resized weapons/armor", is fixed.)
There seems to be an additional problem with resizing the rods that are also weapons, so I'll make another JIRA for that.
The linked issue should be resolved in 6.01.05. Retry your fix.
Resolved a long time ago... Confirmed fixed.