What is the difference between the sub-naval storage centre and the primary chakra very adjacent to it... are they the same thing???

Sorry if this is a stupid question, but the location of some of the secondary and primary centres is somewhat subjective (in my opinion).

my understanding was that if I just put energy to my sub-naval... then its the sub-naval... but if I spin, and overly 'open' that area, then it's the primary centre...

An explanation would be mighty fine ;o)

PS - that also goes for the sub-heart and the sub-brow centre