On a normal server nobody crafts these. The game gives players no way to craft or research the rocket, so the Level 3 recipe stays out of reach and every one comes from loot, as the item page says. What the calculator does is tell you what you are holding: a long gun powder queue and a pile of metal pipes that no group would spend on one barrage.
So the real choice is fire or recycle. A volley needs an aiming module and people who can hold the truck while it shoots. If your group will never take the MLRS, the rockets are just pipes in a box. The recycler hands back half the powder and two pipes from each one, exactly the pipes of an ordinary rocket.
Tip
Decide before the recycler, not after. Once a looted rocket is broken down, nothing on your bench can put it back together.
