I rather suspect those tubes are 300mm.
I think your problem is that Uragan means Tornado and so it is getting confused.
the whole idea of a palletised system would be one heavy platform that can carry either light (122mm Grad) medium (220mm Uragan) or heavy (300mm Smerch) rockets in reloadable pallets.
Another system on a lighter truck that was more mobile and could perhaps only carry the lighter rockets would be useful, though a lighter truck version with a pallet load would also add all the advantages of pallet loads as well as offer the flexibility when loading with a wider choice of rocket types and calibres.
the Amusing thing is that if the target is an enemy grouping of armoured vehicles 30km away loading up 122mm rockets actually offers the best solution as the 40 tubes with two anti tank top attack guided sensor fused submunitions means 80 tank killers with the 122mm version while the 300mm model carries 5 munitions per rocket, but with just 12 rockets, that means 60 munitions... though the 300mm system can hurl them to 90km which is rather further than the 122mm which can only reach 30km with the same weapon system.