Create a new mission in editor (basic to avoid any lag problem).
Choose Stratis, place a M4 Scorcher in grid 037048 or more exactly 0375 0488 (near hill 214), let it North oriented, place your player unit (spotter or else) near stratis airfield (i.e. 0227 0492) to have the airfield in sight, but you can choose another place)
place support requester & support provider modules as usual (if virtual artillery, place the virtual artillery provider module on the same position (hill 214). Run the preview.
Aim at tent hangars (0173 0520) and ask for artillery support. Check by the way ETA in sub-menu title (something about 30sec for M4 155mm shell, 25sec for mortar shell, 43sec for MLRS ammo).
You can trigger a real chrono at "ordnance is inbound" or when artillery shots if you stay near from it. watch for impacts.
flying time of shell is OK for mortar and MLRS, wrong for M4 Scorcher : about 50sec instead of 29!
Shoot in other directions : this could be fine. Return to shoot tent hangars, shells are 20sec late!