Well. "the company purchases the license to use at work" isn't really what they do. They buy a license to enable them to produce product. Where its produced is irrelevent. I suppose an analogy (albeit a poor one perhaps) would be you don't need a different insurance policy to drive a company car out of work hours.
However the arguement would be along the lines of "if they (the company) hadn't bought the software/license. Could you have legally produced the code?" The answer is only a difinitive "yes" if you have a license in your name, that you have bought. Otherwise you have used a company resource as they have the payment receipts, license and inventory ledger stating that they have it, You, on the other hand, merely have access to it whilst you are in their employ - under their license). Combine that with the work for hire clauses and you really don't have a leg to stand on.