You might consider referencing the actual date/time in the source column for Quote_Month
, then you could transform your OR
into a couple of AND
s, something like (assuing the date's in something I've chosen to call Quote_Date
)
=SUMIFS(Quote_Value,"<=90",Quote_Date,">="&DATE(2013,11,1),Quote_Date,"<="&DATE(2013,12,31),Salesman,"=JBloggs",Days_To_Close)
(I moved the interesting conditions to the front).
This approach works here because that "OR" condition is actually specifying a date range - it might not work in other cases.