Anyone know anything about new battery saving email "feature"

So, I went into sprint today because I wasn't getting alerts when I get new emails. The guy at sprint says it is a feature for the s30 where if you have it set to only pull the 25 most recent emails and your box has more than 25 emails it won't alert you. He said that somehow this saves on battery, but it just seems plain dumb to me. Now that I changed the setting to 75 emails (I have 68 emails in my inbox), I am now getting alerts. Anyone know about this "feature"?