SUM Function not calculating properly

Here's the scenario:

I have 5 connected spreadsheets in a workbook that I maintain, but did not design. One, entitled 'Scores' holds a list of employees & their location and their graded call count for the month. I then have 'Combined Trends', 'L1 Trends', and 'L2 Trends'. They are essentially the same spreadsheet as 'Scores', however 'L1 Trends' is set up to only display the call count for Location 1 and 'L2 Trends' only displays the call count for Location 2.

On the last worksheet, 'Stats' The call count for Location 1 is 317, Location 2 is 756. I've checked it multiple times, and the Sum at the bottom of the page confirms that. However, 'Stats' also shows the total call count (From 'Combined Trends') is 1086! 317 + 756 = 1073, not 1086. I can't seem to figure out why there is a discrepancy of 13 calls.

The same sort of small discrepancy also appears for the SUM of Green (score greater than or equal to 80) and Yellow (Score between 70-79) calls, where they are off by 5 and 3, respectively.

Here are the formulas:
In 'Stats'
=SUM('L1 Trends'!L:L)
=SUM('L2 Trends'!L:L)
=SUM('Combined Trends'!L:L)

In, 'Combined Trends' example of call count pulled from 'Scores'
=IF(ISBLANK(Scores!H3),"",Scores!H3)

In 'L1', call count pulled from 'Scores'
=IF(ISBLANK(Scores!H3),"",IF(Scores!A3="L1",Scores!H3,""))

In 'L2', call count pulled from 'Scores'
=IF(ISBLANK(Scores!H3),"",IF(Scores!A3="L2",Scores!H3,""))

Because I had been searching online for the answer before asking, I have already changed the format of the cells to Number just in case any were accidentally Text. Please help me! This is driving me batty, and its making my spreadsheet inaccurate.

May be
=IF(ISBLANK(Scores!H3),"",IF(upper(trim(Scores!A3))="L2",Scores!H3,""))