We can count but unlike you, we also consider other factors in war, such as weather. China have only two windows, March-Apr or Sept-Oct, and each window is about 2-3 weeks before the weather become too harsh to sail the invasion fleet. In Desert Storm, our air campaign was 40 days and that was our decision. China will not have that luxury.
Not only that, the 'tooth to tail' ratio T3R is unlikely to work for China. T3R means the ratio of support troops per combat troops. But if strait weather discourage or even outright prevent such support, an invasion is practically impossible.
en.wikipedia.org
Now, am a USAF guy, F-111 (Cold War) then F-16 (Desert Storm), so I will use the Vietnam War as example. Over Viet Nam, the US was numerically superior to the VPAF. So what the MIG-21s did was hit-and-run tactic. The MIGs would dive and shoot at the bomb heavy American fighter-bombers, compelling them to jettison their bombs so they could maneuver. It does not matter if the MIGs had any kills. Their missions were to discourage the Americans from delivering bombs on North Vietnamese targets, and the VPAF succeeded many times.
What make you think the Taiwanese cannot do the same to Chinese pilots? And how long do you think Taiwan can keep that up? Not only that, we are not talking about the ROCAF but also Taiwanese air defense missile batteries. The four-ship formation is combat tested. For every PLAAF four-ship flight, all Taiwan has to do is hit one to reduce combat effectiveness of the attackers. All Taiwan has to do is survive that 2-3 weeks window and with US support, they certainly will.