Would RIP software help me adjust the length of my iPF9400S prints?

We use an iPF9400S to print inspection mylars for sheet metal parts. We have good luck with it over the last year, but we're finding that it's not producing prints of accurate length. It's not really noticeable for shorter prints, but last week I printed a sheet for a piece that is produced with a length of 145.588 in. The print came out to 145.47 in. The printer provides adjustment in increments of .02%, so I dialed it up a notch and the next print came out to 145.67. I really need it to be ±.030 in for QA to give it the OK, so I'm wondering if there is a third-party solution that would allow me to adjust this.

Thanks in advance.