Yep that's a gobful...
It's been known for some time that a large number of people who report "reactive hypoglycemia symptoms", don't actually have a hypoglycemia blood sugar. This is very common, far more common than actual reactive hypoglycemia which is relatively rare.
Idiopathic Postrandial Syndrome is a name that has been given to the condition where as above, patients suffer hypoglycemia symptoms without the hypoglycemia blood sugar level.
Unfortunately not a lot is known/documented/recognised with this condition, just like reactive hypoglycemia, it goes undiagnosed too often.
The two are very easily confused since the symptoms are just about the same, even the treatment of the two conditions is just about the same. Diet.
With regards to treatment, due to it being similar for either condition, it's not too important that you distinguish which condition you have. But with regards to diagnoses and possible underlying issues, you should make the distinction and make sure that you are (or are not) suffering a hypoglycemic blood sugar of 2.4mmol or under when symptoms occur.
Here is a small link to Wiki with a more understandable description:
http://en.wikipedia.org/wiki/Idiopathic_po
stprandial_syndrome