UNSC Ship costing

I just altered the Sol class SDNX to fit my specifications but can't
seem to
work out the points, well I think I can't anyway, but then I can't get
the
Sol class cost to match that on the SSD either.

The SSD is at www.maljazar.co.uk/UNSC/UNSCAjax.jpg

I started with the Sol class and modified as below:

Removed the fighter bay
Dropped the thrust to 4
Added an extra P Torp (3 arc)
Added 2 extra Graser 2's (1 arc)
75 Hull Boxes rather than 72

Ajax class EXTENDED RANGE SUPERDREADNOUGHT			
								MASS   
COST
Mass						260			
Hull						75		75     
225
Thrust					4		52	104
FTL						1		26     
52
Fire Controls				4		4	16
PDS						4		4      
12
Level 1 Screens 			1		13	39
Class 1 Beams				2		2	6
Class 2 Beams				4	6	10	30
Class 2 Graser (1 Arc Standard) 2	0	18	72
Class 3 Graser (1 Arc Standard) 1	0	24	96
AMT Missiles				6		12	48
Pulse Torpedos				2	4	12	36
Cargo Space					8		8      
24
				
								260    
760

What have I done wrong?

Paul Owen