Calculation of Fulltime Research experience

[Melchy]

Can somebody give me their perspectives on this issue regarding PhD applications.  I grossly under-estimated my years of fulltime research experience, going by the way the schools asked that such experience be calculated. I just realized it upon revisiting my application.

I am disturbed about it. I stated over 16 months, while I should have said something like 36-40 months.  Will that weaken my application?  I am also not sure whether first-author book chapter publications count as part of peer-review publications. Can someone clarify for me, please? Thanks in advance