General NDMP backup question

Hello all,

Really hoping someone can help. I was briefly considering doing a monthly NDMP full backup complimented by differentials in between for one of my NetApp filers. At some point thereafter, I was advised that I can put said schedules in place, howerver, NDMP will NOT allow for that timeframe between fulls. i.e. it will execute a full on it's own. Is that accurate? I can't find much information on this.

Thanks, Joe