Help with formula please.

[SS]

I posted this a couple of days ago but doesnt seem to have appeared so I
hope this is not a duplicate.

Original formula from previous post...
=(("12:00"-MAX(C11,--"7:00"))*0.3+(MAX("23:00",C11)-MAX(C11,"12:00"))*0.4+(C12-MIN(C12,"23:00"))*0.5)*24

I have changed the formula to

=(("12:00"-MAX(C11,--"7:00"))*0.3+(MAX("23:00",C11)-MAX(C11,"12:00"))*0.4+(C12-MIN(C12,"23:00"))*0.5)*C13

As a test I have put in aircon running for 1 hour between 10-11 am

So this should return a value of .30 It is however returning a value of
2.17 Can anyone help with this. Thanks


Original post.....

I am trying to work out the cost of running an aircon unit.
The electricity costs are different during the 24 hour day.

In cell C7 I have costs per KW from 06.59- 12.00am (lets say .30 p an
hour)
In cell C8 I have costs from 12.01-22.59pm (lets say
.40p per hour)
In cell C9 I have costs for 23.00 - 06.58am (lets say
.50p per hour)

In cell C11 I have time aircon switched on
In cell C12 I have time aircon switched off

In cell C13 I have total hours switched on