Barcode weirdness: Exactly the same, but different

I was transferring an existing production web-application to a new server. There was a slight gap in the operating system version and I ended up refactoring lot of the code to compensate newer libraries in use. One of the issues I bumped into and spent a while fixing was barcode printing. It was a pretty standard Code 39 barcode for the shipping manifest.

The old code was using a commercial proprietary TrueType font file. I don't know when or where it was purchased by my client, but it was in production use in the old system. Looks like such a fonts sell for $99. Anyway, the new library had barcode printing in it, so I chose to use it.

Mistake. It does somewhat work. It prints a perfectly valid barcode. Example:

The issue is, that it does not read. I had a couple of readers to test with, and even the really expensive laser-one didn't register the code very well. So I had to re-write the printing code to simulate the old functionality. The idea is to read the TTF-font, convert it into some internal form and output a ready-to-go file into a data directory, so that conversion is needed only once. After that the library can read the font and produce nice looking graphics including barcodes. Here is an example of the TTF-style:

The difference is amazing! Any reader reads that easily. Both barcodes contain the same data in them, but they look so much different. Wow!

Perhaps one day a barcode wizard will explain me the difference between them.