You're right, maybe you should have read my comments fully and you'll understand that I am not contradicting you.
The stance of Plarium with regards to banking by yellow barring are that it will delay your rewards.
You can find those statements here( https://plarium.com/forum/en/stormfall-age-of-war/-news-and-announcements/25141_the-reward-system-on-battlegrounds-is-now-secure-against-attempts-to-obtain-units-in-an-unfair-way-/), where the CM and administrator stated those fact.
Second thing since BG are resource in resource out, it doesn't matter what method of banking you use. You'll always get a reward. The method of banking only determine WHEN you are going to get that reward in you top level BG.
Yellow barring method will never guarantee you when you'll get a reward, even when you use a ''sweet-spot'' formula you're never gurrenteed that you'll get a reward when using yellow barring method of banking. With that said, Unless you have the ability to buy sapphires then and again and revive your army then is best to use these method, But f not then don't use it especially when you're playing BG higher than level 100.
IF you do use these method, you'll complain( like Thefray above) that BG are broken, there's a bug, BG eat my army ect. These is a largely because of the randomness and factors that must be satisfied when you do BG. Yellow baring doesn't always satisfy those factors, its unpredictable and will eat your army one of these days, and furthermore Plarium doesn't endorse it. So play at your own risk.
Yellow barring in lower levels( max 50) works just fine, and will work for you. Above 100 BAD idea.