According to Dictionary.com continuity is defined as "the state or quality of being continuous." 

When we are talking about reports, I would assume that could be interpreted loosely as "the same throughout".  Therefore, when you make a reference or interpretation you should use the same format or keep the same opinion/interpretation throughout your report.  I don't know about you, but I try not to confuse my reader.  So, when I read a report that makes multiple references to another report, but uses different names each time (the XYZ Consultant's 2009 Phase I / the 2009 Phase I / the 2009 report / XYZ Consultant's Phase I report), I get flustered.  Yes it is a small thing, but if your referencing multiple reports and call each report many different names, your opening the door to misunderstanding, client confusion, and in the end client dissatisfaction.  Client dissatisfaction leads down a dark road, especially if you leave them feeling like they are missing something, they can not understand your reports, feel you do not have the ability to maintain a continuous thought, or feel your trying to cover an issue. 

Small things may not turn the tide of decision; however, they do make a difference in the end.  Especially concerning your clients perception of you professionalism.  We'll take the example of two consultants that come to the same conclusion for a site report.  Though they are both professionally competent, know the regulations and engineering controls thoroughly, one writes more clear and concise than the other (we will skip client maintenance skills for the purpose of this discussion).  Who do you think will satisfy the client better?  The one who can communicate clearly of course.  Continuity is a major player when it comes to writing clearly. 

If your project is comprised of multiple parcels and you refer to them as "the Property" then "the subject parcels" then "the property parcels" then "subject Property parcels" your not clear in your references.  No, most of us, and likely your client, will understand what your referencing, but why leave it to chance?  What's the difference between "subject property" and "subject parcel?"  The report I read meant the "subject property" was the clients property, and the "subject parcel" was a reference to an adjacent site with known impact.  That type of reference can cause confusion and miscommunication. 

It may sound repetitive or blasé (we're not writing graphic novels here people), but consistency reduces the chance of miscommunication.  As my buddy Jeff Lanier says "Remember to KISS it" (Keep It Simple Stupid).  

Scott