Because I haven't seen many guides or work on it. I put together this simple help guide for players. Let me know if you feel there's further explanation still needed or if you'd like more information and/or screenshots? You can see my previous set of screenshots illustrating this calibration process in-game and showing the before and after effects of calibration:
Further to the enhancement feature introduced in Progression 2.0 is the ability to "calibrate" your equipment. Basically this is a process where you are able to "tweak" the Primary bonus and penalty values on equipment (refer to the table below to see the ranges of these values at each enhancement level). and materials. These ranges overlap slightly, for instance, fully calibrated Improved equipment will be slightly better than a piece that was simply enhanced to the Advanced tier without further calibration. The positive and negative basic effects of equipment are linked and progress simultaneously while calibrating — all new equipment is a compromise between boosting one parameter of an aircraft and slightly weakening another.
Calibration currently DOES NOT affect bonus characteristics, like enhancement, calibration requires credits
As a visual representation of the level of calibration, there is a Technological level meter in the Calibration menu. For each quality tier, it shows how close you are to getting the best rolls. Keep in mind that improvements to the positive effects affect this meter much more than weakening the penalties of the negative ones. There cannot be a “bad” calibration roll where everything gets worse, at least something will be improved. Nevertheless, if the positive effect rolls the same while the negative changes only slightly, the meter might even roll back, though in fact the equipment will still become a little bit better. You can "re-roll" a negative calibration by clicking "calibrate" again and it will not apply the roll then complete another roll costing you credits and/or materials again. If you like the roll, you will need to apply before calibrating again or leaving or you will lose that current roll and the resources spent.
It is important that some players will keep pressing calibrate thinking that it will be pure RNG if you get a max roll. It is possible and easier to accept lots of small increments for calibration rolls and building on them, rather than wasting resources continually rolling trying to get a max roll which will be unlikely.
As the same with enhancement, the table of values for the max primary stats are available in the table