Need to know that how many number of sums we can use in a single line item so that its performance will also won't downgraded.
Performance depends on the various factors like size of modules used in Sum, Summary methods, Multiple If else statements. There is no straight forward answer to the number of SUM can be used in a line item, you can test the performance in real time environment. If it affects the performance, try to break the formula in multiple lineitem.
It really depends on what you are asking…
Hope this helps,