|    A    |     B    |    C     |
--|---------|----------|----------|--
1 |    10   |          |          |
2 |         |          |          |
3 |     0   |          |          |
4 |         |          |          |
5 |         |          |          |
6 |         |    5     |    7.5   |
7 |         |          |          |

In Cell C6 I want to calculate the average of different numbers that are in various cells in the sheet.
In the example these are the cells A1, A3, B6.
Additionally, I want that in the average calculation cells with a 0 are ignored.
Therefore, in the example only Cell A1 and B6 should be considered –> C6 = (10+5)/2 = 7.5.

The issue is that these values are not organized in a column or row and therefore I am not able to use the =AVERAGEIF function. I tried to apply the solution from here but instead of 7.5 it returns 15 so it sums up the values and does not build the average.

=SUM(A1+A3+B6)/INDEX(FREQUENCY((A1+A3+B6);0);2)

Do you have any idea how to solve this issue?

Note:
I know in the example above I could solve the issue by simple not include Cell A3 into the average calculation. However, in my original file this number can always change so it can be either 0 or some other number. In case it is not 0 it should be included in the average calculation.