Why is there no neutral lunar month and solar terms?

24 solar terms has a solar term every15th day, and the lunar calendar has 29 or 30 days every month, so there must be a solar term every month, but China may not.

Lunar calendar 19 arranges 7 leap, and lunar calendar 19 must be 7 neutral. It's not a coincidence, but it should be.

Because the solar calendar 19 is definitely not short of qi, but seven months in the lunar calendar will inevitably lead to the shortage of qi.

Due to artificial regulations, the lunar month must be neutral, and in 19, it must be 19X 12=228 (neutral).

But in fact it is only:19x29.5306/30.4369 = 221.21(neutral gas).

There are 7 neutral periods in 19, and leap months are set in months without neutral periods.