Little Fess or Adult Fess for babies?

Recently we have been battling a baby's blocked nose and asked the question whether we should use the adult Fess saline solution or the exorbitantly more expensive Little Fess. We noticed that recently, the adult Fess bottles have changed their labeling to say that it is not suitable for babies which was not the case before. On their website, it says this -

FESS Little Noses Spray is ideal for older babies who tend to wriggle around a lot. The spray is preservative and additive free with a unique filter in the bottle to keep the saline hygienic and germ free. It also comes with a FESS Nasal Aspirator to gently remove excess mucus. The FESS Little Noses drops bottle makes it ideal for newborn babies by allowing a more gentle application of non-medicated saline into the littlest nose. FESS Little Noses Spray is also individually packaged and therefore, is ideal for parents who may already have an Aspirator.

A little digging and we found that the preservative used by Fess called benzalkonium chloride for the adult Fess, could be doing more harm than good. Our conclusion was to go for the expensive Little Fess which is much cheaper at Chemist Warehouse than other pharmacies ($8.39).