DLA HR Mobility for the blind or severely sight impaired

I’ve opened the statutory instrument to try to find out the timescales of this very welcome (and long overdue, may I add) change in the law but I’m still confused! Do you clever lawyers understand what it’s meant by:

“These Regulations come into force:

(a)
for the purposes of assessing claims and making decisions on eligibility, on 15th October 2010; and .
(b)
for all other purposes, on 11th April 2011.”

I’ve rang the DBC Birmingham and asked them if the new rules would apply to new claimants from 15th October and to existing claimants from 11th April, which was my interpretation. However, all they could tell me is that they will be contacting existing DLA claimants who now qualify for HR mob for reason of being blind or severely sight impaired from the end of 2010 and they will ask them questions on the telephone. That’s all they could tell me! Does anyone know more or can interpret the SI better than me?? Link below:

http://www.opsi.gov.uk/si/si2010/uksi_20101651_en_1