select all presets containing a specific channel

perhaps this would help you:

change to blind

select all presets "Preset Home thru #"

change with format to spreadsheet (not important but you better see what you did)

Chan 81 shutter mode 100 (or whatever the wrong value is) Replace with 50 (or whatever the right value is)

this change in every preset with a recorded chan 81 shutter mode with value 100 the new value 50

Replace, that might be the key, i'gonna try soon, but it seems perfect!

Replace, that might be the key, i'gonna try soon, but it seems perfect!