Query on IF - Filter - and condition

[VBABEGINER]

Hello board,

I've already dax formula with me. but now very confuse and dont understand how to question here.. hence wanted to go step by step solution..
below is my current dax -

Issuance = 
Var a=
CALCULATE(COUNT('SRQ'[ID]),
FILTER('SRQ','SRQ'[Request Type - Prod]="Midterm"),
FILTER('SRQ','SRQ'[Total Cert]>=1))
+
CALCULATE(COUNT('SRQ'[ID]),
FILTER('SRQ','SRQ'[Request Type - Prod]="Renewal"),
FILTER('SRQ','SRQ'[Total Cert]>=1))


Var b=
CALCULATE(COUNT('SRQ'[ID]),
FILTER('SRQ','SRQ'[Request Type - Prod]="Midterm"))
+
CALCULATE(COUNT('SRQ'[ID]),
FILTER('SRQ','SRQ'[Request Type - Prod]="Renewal"))

return
a/b

now additional condition's are -
if my center = Mumbai then filter --
'SRQ'[Project Type]="Undelivered" AND 'SRQ'[Working Client Region]="Admin" & "Process Support"

if my center = Manila then filter --
'SRQ'[Project Type]="Undelivered" only

and should perform above calculation i.e. var a and b



Can any one please guide here...

 

[VBABEGINER]

Pls suggest here..

 

[VBABEGINER]

Is my query not understand?