Here's a link for a thread here regarding them:
https://forums.frontier.co.uk/showthread.php/409336-Deep-charge-vs-Mass-manager
Within that thread is also another link with the math behind it, so those commanders deserve any appreciation for their work.
Ultimately it depends on factors including the weight of your ship, here's a snippet of my spreadsheet, using the Python (Cargo configuration, so sub 600T IIRC):
I didn't try Deep Charge due to above linked reasons, but you get the general gist. As I said, it changes depending on mass, so YMMV.