I need to check a value in a existing list, if the value doesn't exist give extension _00 but if exist increase value by 1 (i.e. _03) in excel.
Example
1.- Value to check from the list below ***-DWG300
2.- Value to check from the list below AXT-TST400


ATS-ADS100_01
ATS-ADS100_02
ATS-ADS100_03
***-DWG300_00
***-DWG300_01
***-DWG300_02
***-DWG300_03
***-DWG300_04
***-DWG300_05 (1.- this should be the new value added to the list)
AXT-TST400_00 (2.- this should be the new value added to the list)

Thanking you in advance.
Luis