Confusion on Fighter costs

This may seem very basic, but after looking through the FT and MT rules,
a
couple of the different ship building spreadsheets, and a FT Build
Reference
spreadsheet, I have some confusion over the mass of various fighters.  I
know that the basic fighter mass in FT (including the bay) is 3.  The FT
Quick Ship Design Reference Sheet agrees with this.  This sheet also
goes on
to give the masses for a variety of different fighter types, ranging
from 3
to a max of 8.	This reference sheet also gives the squadron costs also.
The problem I have is when I compare these costs to those listed in the
following shipbuilding spreadsheets: thrust.xls, FT_BLD and FT_BLD_5. 
In
the calculations for the total mass for the fighters, they use the set
value
of 6xnumber of fighters.  What is the generally accepted mass values for
fighters? 
		Kent McClure
Current fleet in progress:  a non-FTL fleet based on Flash Gordon style
ships.