STAAD.Pro V8i Seismic Definition (IBC 2006)

Currently I've been doing seismic analysis for our cracking furnace.

Let's just say I was advised to consider Primary Loads 1 to 6 as seismic weights for the seismic definition. (1 to 6 are basically dead loads)

The code currently looks like this:

DEFINE IBC 2006 LOAD

ZIP *etc etc etc seismic parameters bla bla bla*

Then, for the seismic weights,

Basically I converted all the Y loads from the load cases and changed them into weights the conversion looks like this

JOINT LOAD                                                                             JOINT WEIGHT

XX XX XX XX FY -J                                                                    XX XX XX XX WEIGHT J

MEMBER LOAD                                                                       MEMBER WEIGHT

XX XX XX XX CON GY -K                                                         XX XX XX XX CON K

XX XX XX XX UNI GY -L                                                            XX XX XX XX UNI L

ELEMENT LOAD                                                                      ELEMENT WEIGHT

XX XX XX XX PR -M                                                                  XX XX XX XX PRESS M

However, I discovered an easier solution, to declare the primary load cases as reference loads BEFORE the seismic definition, and loading them as so

REFERENCE LOAD Y

R1 1.0 R2 1.0 R3 1.0 R4 1.0 R5 1.0 R6 1.0

My problem is, when I check the "PRINT STATICS CHECK" output, the values ARE NOT the same and it looks like the REFERENCE LOAD produces lower applied loads.

Any ideas?