That's some incredibly bad reporting and fuzzy math presented as facts:

The contract stipulates the creation of over 100,000 units of 155-mm ammunition via Expal, a Spanish company Rheinmetall recently acquired in November 2022 for a hefty sum of 1.2 billion euros.

Other, more credible reports state that the order is for several hundreds of thousands of DM121 shells - meaning the math here could be easily off by a factor of three or more.

Even Rheinmetall's own website states that the order is for several hundreds of thousands of shells.

Which would mean that these shells would cost about as much as they always have, and maybe even significantly less.

Even if we use a “mid-range” estimate of €400 million for the 100,000 shells, that still leaves each shell costing €4,000.

I tried digging up US pre-war costs for a standard 155mm HE shell, earlier in the year, and found numbers online that were in the high $800 range. This is five times that. The munitions manufacturers are making bank on their pricing.

EDIT: Well, okay. Some of that could also be reduced efficiency, maybe due to reduced economy of scale; there are a number of manufacturers in Europe picking up the contracts. I don't know what a typical pre-war shell price was in Europe.

And some of it is gonna be that a lot of capital goods used in production, machines and the like, were paid for way back. The new shells are gonna need new machinery and such.

It is a lot more expensive, though.