Found out the  hard way a few projects back - if you use anything longer than  ONE character for the first reviewer  abbreviation, the entry in the Submittal Register will be split into two rows,  with no reviewer on the first row, and the second row being empty except  for the reviewer abbreviation appearing in the submittal item column.   
  
 The rule of  thumb is the first abbreviation must by one character (such as "G" for  Government review), and the second abbreviation can be 1 or more characters,  apparently limited to 3. Refer to the editors notes in any spec section, and it  will give you the run-down on the meaning of each standard abbreviation used by  the Army. The Navy, Air Force, and NASA typically only use "G" and no other  codes after that.
  
 Problems will  arise if, for example, you wish to use an Architect/Engineer designation (often  "AE") or Designer of Record Approval ("DA") without preceding it with a "G". The  format must
 be ..; <SUB>G, AE</SUB>. You can not  use ..; <SUB>AE</SUB> or your submittal register will look like  this:
 
  
 What you  really want is something like this:

  
 
...but then  it requires you to also have Government review (probably a 30-day process which  is not popular on Design/Build projects unless it is really meant to be  required).
  
 Now that LEED  is becoming predominant on many Federal Government projects too, a whole new  level of review is being added to the process -- something this system  doesn't seem to address consistently yet in the UFGS masters, nor in the  submittal register at all.
  
 After a lot  of experimentation, it finally became clear that the problem revolved around  using anything longer than one character - unless you have more than one review  abbreviation, then it seems to accept up to three for the second  abbreviation. There can be no more than two abbreviations, or it will either  spill over into the Contractor schedule date column, or start a new blank row  and drop them all there.
  
 Examples of  failed attempts to use more than 2 reviewer abbreviations:
 
  
 
A compromise  that is being successfully used on one of our projects now is to abbreviate  Designer review as simply "D", and LEED review as "L". Looks like we will be in  good shape as long as we don't need all three for the same item! This may or may  not work for Army projects either, because they often require "DO" District  Office, "RO" Resident Office, etc.
  
 So our  introductory paragraph in submittals reads:
    Government approval is required for submittals with a "G"    designation.  Submittals having a "D" designation are for approval by the    Contractor's Designer, either the Architect or Engineer as appropriate for the    discipline. All other submittals are for Contractor Quality Control    Approval.  [When used, the designation "L" following the "D" designation    indicates that the Project LEED Accredited Professional  will review the    submittal. ] The following shall be submitted in accordance with Section 01 30    00 SUBMITTAL PROCEDURES: ...
  
 Please  comment if you have explored this at all before, and if you have any reactions  yet from Government reviewers on variations in the use of this system. This  posting is simply to share the tiny bit of knowledge about which number of  characters will do what and where.