Calculating time OR age in days, hours, and minutes between two dates

I am trying to calculate the time between two dates, excluding weekends (I'm not too worried about holidays). I have five columns: Received, Completed, Time to Complete, Age, Finished

I have found a formula that works between the Receveid date and Completed date when they are farther apart than 31 days:

ex: =NETWORKDAYS(A8,B8)-1-(MOD(A8,1)>MOD(B8,1))&":"&TEXT(B8-A8,"hh:mm")

But I also want to calculate the AGE of the job when it hasn't yet been completed, and with the formula above, the Time column displays an error, and I want it to remain empty. Please see the attached sample to see what I mean. Row 3 shows how I want it to look when the job has not been completed and it displays the age (but you will notice that the age is not correct as it would be 3 months old at this point). Row 4 shows what I want the Time and Age columns to look like when they have a value in them. And Row 5 shows what the Time columns look like with my current formula when the job has not yet been completed.

So the two problems are:
1 - calculate the Age when the two dates are farther than 31 days apart.
2 - when the Time column is calculated, the Age column should be empty (and vice versa)

Thanks for any help in advance!!!!

hello commanderboo, welcome to excelforum. Try this for C3 copied down

=IF(B3="","",NETWORKDAYS(A3,B3)-1-(MOD(A3,1)>MOD(B3,1))&TEXT(B3-A3,":hh:mm"))

and this for D3

=IF(B3="",IF(A3="","",INT(NOW()-A3)&TEXT(NOW()-A3,":hh:mm")),"")