As per my point of view,...

Example 1h 55m + 1h 50 m
Add 155+155 take 55 + 55 =110 , nCount=0
Now compare it with 60 (if 110 > 60 ) 110 - 60 =50 ++nCoun;
Answer will be (1+1+ ncount)H 50M

Example2:
1h50m + 1h 50m + 1h 50m
=> 50 +50 +50 =150 which is greater than 60 => 150-60 =90 , ncount=1
=> till less than 60 i.e. 90 - 60 =30 , nCount =2
=> So answer will be 1h+1h+1h+2=5h 30m


NOTE: It's slightly diverse from your type of solution ...