ippsFFTGetSize_C_32fc pBufferSize Question

Hi,

I am using ippsFFTGetSize_C_32fc() to size for a FFT with an order of 19. The pBufferSize calculated is 262,208. However, if I size a FFT with an order of 18, the pBufferSize is 2,097,216. I expect the larger FFT order to calculate a larger pBufferSize. Is this assumption incorrect?

-Treph