Well, I do exactly the same thing.
But what I'm trying to tell. Suppose you get Computers (like 10 turns worth of research) with Liberalism (2 turns), this way saving yourself 8 turns. However to get to Computers you need a long line of techs Astronomy -> SM -> Physics -> Electricity -> Radio, which is by itself like 30 turns or something.
Now if you get Something with Liberalism early, like Astronomy (5 turns), you save only 3 turns, but you get Liberalism's own benefit like 25 turns earlier.
I myself usually do not rush to Scientific Method, because it cancels GL and Monasteries. Now, a monastery for +10% research is worth only 60 hammers, and 3 monasteries worth 180 hammers for +30% research is better than a lab for +25% research worth 250 hammers.
For this reason I really like to research Assembly Line and Railroad before SM, and only then rush to Computers after Physics and Biology.
In this game I also made some serious mistakes, but it was all about conquests, not teching.
Like I captured one of the capitals with 12 floodplains 1000 years later than I should. I was struggling to build a library in this city around 1000AD while running Representation/Emancipation (no rush option.)