Amanda’s suggestion seems sensible.
I would have thought a reason to note the length of depositions was if they broke any of the rules about the length of the papers in cases. Those rules were often broken, but a breach might be something a reporter would consider noteworthy. If that is correct, might the “K” be an erroneous character for a number (perhaps “L” for 50?)?
My impression is that reporters often had something of a blind spot for numbers (copyists even more so) and if memory serves, Hawarde wrote up his reports from notes taken earlier.Taken together, it might be that Hawarde made an error about a number related to the length of the depositions when writing up his reports.