ewbie
there are as many fertilizers as there are growers ,as all growers will end up using something different.
Here in new zealand the fertilzers are labeled different to where you are,we have the actual N,P,K, rating expressed as a percentage.Under my conditions I have two fertilizers that I use,one for growing and the other for flowering.Generally the growing fert is a high nitrogen and the flowering has lower nitrogen and higher Potastassium.
So I am using a (as percentage.27/5.5/9 for growth at 1/4 strenght 1-2 times per week and 15/4/26 about 2-3 times per 14 days)I have found ,for me that in the growing season if I stay with the high nitrogen fert ,the plants are way to lush.

Having Dendrobs and Vandas is no problem , as both have a growing and flowering season.
The Dendrobs will grow and flower while at rest,and at this time there is very little growth and therefore will not need feeding.
The Vandas on the other hand grow all year and can flower at any time,therefore a fert lower in nitrogen would be better as they are feed all year round.
As for feeding young plants a high nitrgen fert , that is to get the growth as they are not going to flower.Not seeing a difference in the vanda since you have been feeding it the high nitrogen would not be uncommon due to the fact that the vanda does not have to grow as much to flower again,and is also aslower growing(imagin a vanda growing the equivilent to a cane of the Dendrob).

By the way the Dendrobs that you will be growing will be HARD CANE ,and they are covered under this thread
http://www.rv-orchidworks.com/orchid...splay.php?f=60