That problem is with the calculation formula in section of evaluating of "ahead of time" modifier IIRC. There plays a role three things - current year, average year of accomplishment (that one in tech file), and some hardcoded year around 750. The last value works as a base for calculating modifier for increasing prize during time. In that year the modifier is 1, the further from this year the modifier increases and so does the tech prize. If you're using years before 750, then the modifier decreases and the prise is dropping rapidly. This way you may end with tech prize 0 for several levels and you have new tech level every month.
You must play a bit with the years in tech files to increase the prize somehow. Increase the years for the first levels so the ahead of time modifier will be higher. In the year 711 it shouldn't be that large problem.
Large problems are with scenarios around year 0, where a change by one year in tech files makes a difference of decades or centuries in game.