Formula to calculate sales data as per conditions

[zoharb]

Respected,

has to select range each time for month wise increase/decreased calculations of sales by particular type
(done using SUMIFS and COUNTIFS)

formula should only work if client Id is same & MM-YY is previous month
(done using TEXT() and VALUE())

Also someway to select the range automatically for SUMIFS and COUNTIFS,

so even after insertion/deletion of NEW record, range gets adjusted accordingly
and has not to do it manually.

Zohar Batterywala