Thanks for that formula - I've changed the sheet a bit and its not quite working so I'm wondering if you could have a look at this version? Also I'm trying to point some of the figures into the tabs prior including adding up partial days so I've added in a line to calculate. I managed to add a few things manually through a TC calculator I found online (https://current360.com/apps/timecode-calculator/tc.html) but it stops when it hits over 100 hours. Wasn't quite matching up. Anything your able to shed a light on would be helpful. Thanks in advance.
In attached file there is a small difference with calculator you mentioned. In calculator if enter the time with frames like 20:42:16:10 it shows 20:42:16:11, i.e. adds one frame to each entered value. Don't know is that by design or bug.
In the attached file calculated results are on the right from your ones.