So on the doctrine web page, many of the units have bonuses to the effect of +/- days of availability. I was curious to see what exactly this means, if +1 days means you have to wait an additional day, or if they are available one day sooner. I also don't quite understand what it means when it lists things like +1/+2.

So, I had a friend of mine, who is playing Comintern in his current game, take a picture of his tech tree. I compared it with mine, Allied, to see if I could ascertain what these meant. Allied antitank guns are said to come in at +1/+2 days availability, while Comintern antitank guns have no availability bonus.

But, in practice, there is zero difference. Both doctrines receive antitank gun research on days 1, 3, 6, 10, 14, and 18.

So, what the hell? What does +1 mean? Furthermore, what does it mean when it says +1/+2? How are we supposed to read the doctrine bonuses?