Redundancy Payment is this correct.

I did post a qustion before but am still not sure on what i should be paid. Our HR Manager was himself made Redundant end December and before he left knowing I was liking to be made redundant gave me a projected calculation , however this differs with my letter of redundancy received today. The facts are as follows :

1. Birth Date 31/01/1955
2.Date of Commencement of Service 17/03/1997
3.Salary Over the Maximum £330
4. HR1 Information to Goverment stated 31/01/2009 as 1st Proposed Day of Redundancy (I have a copy of this)
5.Letter today states 30/01/2009 as termination. (assume because this is last weekday).
6.After the 30.01.2009 they are paying me 12 weeks notice pay.

So Question is - they are paying be 11 years service Redundancy Payment (16.5wks). Is this correct as I would have 12 years service in if I worked the notice period and also be 54. And secondly , while I understand it is because of payment being made on a week day (30th), can they bring forward a day the redundancy notice after advising the Goverment of 31.1.2009 being the earliest day. Had the 31st been on a weekday then that would I assume been Redundancy Day. I amm salaried and always paid on last day unless it falls on a Weekend.

Thanks

Not sure if making clear total,but on 31st Jan I would be 1 year older therefore would received additional 1.5 wks Redundancy Pay. Also if this was ignored, if my 12 notice pay was taken into account this would take me to 12years service and not 11 years, again 1.5wks more Redundency Pay than amount I have been notified today