Mr C H, actually do have an effect. E.g., years ago when there was a place called Harrogate, a woman (I would have said smart young lady but I can't now) rang me up. Now I was a lowly officer in Ops but she bypassed Command, Group, and Eng Wg, and said as how we had a standing order for some 20,000 cartridges per year but nil expenditure. Could she suspend the contact for that year?
I realised what was happening and suspended the order. Other than that woman at Harrogate, no one on the engineering or supply side had seen the problem. Indeed some chief on the other side of the airfield was probably wondering where to put them.
Now aircraft spares used to be calculated carefully at CSDE, IIRC, until we ordered the E3 in short order. Now an aircraft already in Service for many years, the manufacturer should know shouldn't he?
So we asked Mr Boeing for a truck load of spares. An opportunity of a life time and he cleared his shelves - mostly spares the USAF hadn't needed (at least that was the story).