Adding increments over minimum number

[BradleyN1]

Hi

I need help with formula
So I have a spreadsheet, example

A1 heading- Minimum number of tasks
A2 '5'
B1 heading- Actual completed
B2 '6'
C1 heading- Total incl over achievement
C2 6.5

I want a formula which adds 0.5 for every 1 added over the minimum (but the minimum may change in the future so can it be set to A2 rather than a '5' number)

So if 6 completed i'd have a total score of 6.5, 7 it'd be 8
However, is it also possible that IF the actual is only 4 (under the minimum) the total would remain as 4? (with no 0.5 added)

Thanks

 

[shg]

	A​	B​	C​	D​
1​	Min​	Comp​	​	​
2​	1​	6​	3.5​	C2: =MAX(A2, AVERAGE(A2:B2))
3​	7​	3​	7.0​
4​	5​	8​	6.5​
5​	8​	4​	8.0​
6​	9​	7​	9.0​
7​	3​	8​	5.5​
8​	6​	7​	6.5​
9​	3​	6​	4.5​
10​	2​	9​	5.5​
11​	9​	6​	9.0​
12​	6​	1​	6.0​