DAX Formula Help

I have two tables in my Power BI, both include a student ID code, a course code, and course credit hours. I want to find the matches between the two tables, where the 1st table (enrollment) looks for matches or no matches on the 2nd table (schedule).  The idea is to look at both the course # and the credit hours to see if there is a matching row of data on the 2nd table. and then on the first table list match or no match for both.   I have been using this formula, and it almost always works but for one student I am getting a match where I shouldn't be.  Note:  it is possible for a student to take the same course # at more than once, but it should only match once. Any help would be appreciated. 

The 3rd link should say no match (8239 at 4 hrs)

Match Status =
VAR _Course1 = 'Enrollment Report'[Course #]
VAR _Hours1 = 'Enrollment Report'[Hours]

VAR _Match =
CALCULATE(
IF(
COUNTROWS(
FILTER(
'Clinical Schedules',
'Clinical Schedules'[Course #] = _Course1 &&
'Clinical Schedules'[Hours] = _Hours1
)
) > 0,
"MATCH",
"NO MATCH"
)
)
RETURN _Match