Buffer size in MPEG-1 Layer III

Folks,

I am looking at the 11172-3 page 33-34, the section regarding buffer
size cosideration, I am quite  about the description:

The spec says the buffer length is 7680 bits and it is calculated
based on 48KHz of sampling rate. The spec also says for sampling rate
lower than 48KHz, the buffer should be constraint such that the same
physical buffer size is sufficient as the one calculated for the 48
KHz case.

If the sampling is 32KHz, the maximun number of bits in one frame is
14400bits but according to the spec, we need to constraint buffer for
this case, but how?

Thanks