This is what happens when you do not follow the instructions in the manual. It all gets very confusing and you end up making mistakes. To time the engine properly read page 18 to 20 of the instruction manual available for download on this site. It even gives instructions for when the marks are missing. (if marks are present do not trust them, people may have altered them over the years).
When you feel confident in knowing what you are doing then by all means experiment with whatever different timing figures you want but it will still be an "experiment".
The figures are Inlet starts to open 27-30 degs (5/16") BTDC
Exhaust fully closed 27-30 degs (5/16") ATDC

Obviously this refers to TDC on the exhaust stroke not the compression stroke.

The figures from Mike Pemberton only puts the exhaust 2 degs out of spec ie 25 instead of 27-30 so could be worth a try.