Change in dose of Toxotere Cyclophosphamide

I have had two of four scheduled treatments with Taxotere/Cyclophosphamide.  Treatment 1 was a horror - I had every side effect possible - thrush, bad mouth sores, yeast infection, hives, constipation, neutropenic fever (WBC <0.1 on day 12 post treatment), throat infection, then diarrhea because of the antibiotics for the fever, etc.   For treatment 2, my dose of both chemo drugs was reduced by 15% (I don't know the actual dose, but was given the typcial dose for treatment 1).  I was also given an injection of Neulasta for the WBCs the day after treatment 2.  I am 12 days post treatment 2 and have had almost no side effects.  I'm not complaining, but I can't help wondering if the lowered dose will be as effective?  Can someone shed some light on this issue for me?  Also, some people seem to get 6 treatments with TC, some only 4.  What factors enter into the decision by the oncologists?  I am ER/PR negative and her2+++, so will start getting Hercepton with treatment 3.  
Thank you.

[Cleveland Clinic]

Dear GS59,  Regimens for treatment of breast cancer can vary in many ways, either by drugs used, schedules, or dosages given.  Many factors are part of the decision of what regimen to give, as there may be several appropriate options for treatment.  There are individual patient factors, such as stage of disease, tumor characteristics (ER/PR status, Her2 neu status) and overall health of the patient.   Then there are also the individual oncologist’s preferences for a specific schedule/regimen. For the most part we cannot determine based on side effects and how you feel during chemotherapy how effective a chemotherapy regimen is.  Your oncologist would be in a better position to discuss with you your concerns about the effectiveness of the treatment now that the dosage has been adjusted.  

[GS59]

I guess I was hoping more for just some information about the research that went into deriving the "standard doses" and whether effectiveness was impacted by higher/lower doses.  It frightens me to think that I may go through the next two cycles of reduced T/C and it may mean that it won't work.  is there a certain threshold that is needed for it to work?
Thank you