Do you have a East-92 to compare? As I said earlier in post #987 here, the diode is likely being used to help with this problem. I could certainly be wrong, but I suspect that the diode may work better. Once the cap is charged/discharged it maxes out. Bigger caps will have diminishing returns & high costs. The diode will continue conducting to remove our stray voltage until Vf is reached.
Good work so far.