Am using Foxit - https://www.foxitsoftware.com/ - does everything that Acrobat Standard did and cost was $129 per machine (one time payment) vs. Adobe Standard $14.99 (PER MONTH) As a retiree, am not sure about Foxit's "enterprise pricing". Also, it seems that some of the pension admin software packages had a pdf generator built in - but that may only work on the admin software output.
I don't think it's odd that they might task you with this since, as you say, you have experience with this area. They aren't going to be able to categorize the experience, it's all the same.
But I do find it odd that you are doing testing and calculations. Is the firm handling all the administration internally? Is there no outside TPA involved?
You could always ask for a raise.