Usage and Grammar

Q. I am having a disagreement over the placement of a word in a sentence: “The estimated cost is 1% higher than the original estimated cost.” I think the word original is acting as an adverb and therefore should be replaced with the word originally, whereas a colleague suggests that original ought to act as an adjective describing cost. What’s your opinion?

A. If you use original, it’s an adjective modifying cost; if you use originally, it’s an adverb modifying estimated. They are both good usages, and the two wordings mean almost exactly the same thing.