Is the aforementioned method of starting ablution directly and disregarding any gas that exits before ablution, during it, or during prayer, correct for someone afflicted with chronic flatulence?

If a person is afflicted with continuous flatulence (sals al-reeh), such that it does not cease for a sufficient time for purification and prayer, then he must perform ablution for each prayer after its time has begun. He should then pray the obligatory prayer and as many supererogatory prayers as he wishes with that ablution. He is not harmed by whatever flatulence is emitted from him, and his ablution is not invalidated by it unless the prayer time expires or another non-persistent impurity occurs. The proof for this is that whoever cannot maintain ritual purity for the duration of the prayer should perform ablution and pray, and he is not harmed by what is emitted from him during the prayer. His ablution is not invalidated by that, by agreement of the imams.