@Fruityloop,
Imagine that you are standing still next to a railroad track and a train is passing you at 60 mph. The boxcars are 1 mile long so that there is 1 minute between the arrival of each boxcar. You now start moving in the same direction that the train is traveling at 30 mph. You will notice 2 things:
1. The train is passing you more slowly.
2. The time between boxcars has increased to 2 minutes.
30 mph is 44 ft/sec. In 2 minutes I travel 5280 ft or 1 mile. That 1 mile is 1 extra minute for the train at 60 mph so the time between boxcars increases from 1 minute to 2 minutes. The train is passing me at 30 mph due to my motion in the same direction as the train. The train was passing me at 60 mph when I was standing still so the speed of the train has decreased relative to me.
In 2.867321 days the Earth moves about 7,379,039 km closer to Algol.
7,379,039 km divided by the speed of light 299,792.458 km/sec is 24.61382 seconds - this rough calculation explains the deviations we see in Graph 2.
What is the difference between my analogy with the train and the timing of the eclipses coming from Algol?