Works for me.
Select the column. Go to Format/Cell/Custom and select the format
hh:mm.
Select the cell you want the total to appear in and, using Custom, enter the format
[hhh]:mm.
Total the cells to be added using either autosum or the formula
=SUM(G2:G19), where G2 and G19 are the first and last cells to be totalled.
I just did it, entered the figures below and got the total as displayed.
08:15
07:12
02:11
02:15
01:15
12:15
11:00
08:15
05:15
22:15
22:15
22:15 124:38