Can you file extension on the basis of L1B+H1B total stay 6 years.

I moved to US on L1B. At the time the extension was due my employer filed my H1B which expires in September 2015. Is it possible to get the extension for another 6 months (By then i will exhaust my 6 year period) or there is no rule for L1B+H1B stay = 6 years