A B C
1 licence No. weight status
2 gmb123r 100
3 gmb234q 150
4 gmb789h 250
5 gmb123r 150
6 gmb123r 275

What I am trying to do is when you type in the licence number and the weight
into coloums A&B, Coloum C returns weither or not the licence is "used" or
"open" and to update for every new row added, recognising that it only takes
away from the one licence total that has been entered.
Licence maximum weights gmb123r=525 so when row 6 is entered all 3 rows
would now say "used"
Also if possible if you entered a weight that took licence gmb123r over its
weight allowance coloum C would say "too much"