anyone else find discrepancies with size of babe?

It seems as though this app might be a bit generous when providing examples of size according to weeks gestation compared to other apps and other size references I've been finding online. For example, every other source says that at about 5.5 weeks the babe is about the size of a sesame seed whereas this app says it is the size of a chocolate chip. Not a huge deal, just seems like a big size difference. Anyone else noticed this?