Hi,
Just played a short game where I produced 2x IS-2, and 4x Katyusha; one of the Katyusha was destroyed. I did not produce or lose any other vehicles.
In the end game stats it showed I'd produced 3 vehicles and lost 1. Not sure if this is a stat you guys influence in the mod, but it appears from this example the Katyusha that's destroyed is the only one included in the built stats.
I'll pay more attention in future when playing Propaganda doctrine to see if this is repeatable.