Total Timing How do you measure it?

[37fatfender]

I am confused as what constitutes total timing. I have read places that all that counts is the initial and mechanical added together equals "Total Advance". That the vacuum advance is not figured into the equation.
I run a modified 8ba with pretty high compression, I have a MSD ready to run dizzy. Its all in at about 2600 rpm. I set my initial and with a digital timing light dial in 26 degree rev the engine adjust the dizzy to line up the marks and lock it down. I then reconnect the vacuum and then my timing is way over 26 degrees.
Am I doing things right?