Evidence that LNVT 37' Hull#61 was Never Built?

The following table was included in Lani Hart's Lord Nelson History letter written in 2010.  In the column marked '37' Tug' there's no hull#61.  From this we can infer that hull#61 wasn't built.  
So, how could a hull number be skipped?  The first thing to know is that the yard didn't assign hull numbers.  They were assigned by Lord Nelson Ltd. on a customer's Purchase Order (see Rose Bud #34 P.O.).   It's probable that a PO was written for hull #61.  But, for whatever reason, the purchase never went through.  

(Editor's note: Adding up the 1986 37' Tug production yields 18, not 17 as shown above.  Adding up the 1987 37' Tug production yields 15 tugs, not 16 as shown above.  The table includes a hull#77--which we have no record of.  This may be a simple error.  Lane Finley bought Lord Nelson in late 1988 so Lani's production count for 1989 could be erroneous. )