Check your math... 40 amps / 160 cells = 0.25 amps per cell
It's more a questions of the actual pack design and how the bus bars are configured... and also if the packs layout allows for an even distribution of resistance so the power is consumed evenly across the pack.
If the pack is build well, 40 amps may be a breeze... is not, you would start seeing issues.
The higherthe load, the more it matters. Combine this with a Hodge podge of mixed cells with varying internal resistance and I can almost guarantee you not all cells are contributing evenly at your 0.25 amp per cell target.
Its fun to poke around with an amp meter of measure the mV delta under load at each branch to get an idea.