ifspeed definition in rfimibv2-12

Hi -

Current definition in rfimibv2-12 draft:

   ifSpeed           Return the maximum channel throughput (not payload
                     throughput) supported by the interface.
                     The maximum throughput is calculated for the case
                     where upstream channels are configured to maximize
                     interface throughput.

In RFC 2670 the definition reads:

   ifSpeed           Return the speed of this upstream channel.
                     The returned value is the raw bandwidth
                     in bits/s of this interface, regarding the
                     highest speed modulation profile that is
                     defined. This is the symbol rate multiplied
                     with the number of bits per symbol for this
                     modulation profile.

Is this a clarification or a technical change?  If the latter, is it due to evolving
technology or operational experience? (I'm just trying to understand.)

Randy