Jayteeto,
Point is that stats can be produced to show just about anything :
7 seperate Police forces who all "use" 135's does not necessarily mean 7 aircraft ( consortiums ).
The ASU's for these 7 forces as handysnaks has hinted at, don't work 24 hrs a day, finishing around 2.30 - 3.00 am and not back on until 8.00 - 8.30 makes 6 hours ( 25% of a day ) unavailable. ( "Ball park" figures taking into account differing weekend working etc ).
One 902 based in the same region DOES provide 24 hr cover so is MORE OFTEN than not available to provide support to those other forces. ( Or at least while it remains servicable for at least 50% of the time
)
NOTHING to do with spares or reliability, just a talking point about "Stats" which don't always reveal the true picture.
Nothing wrong with your maths either - Apology not needed
