Bedroom standard
From the Shelter Website:
This is not a legal definition of overcrowding or a measure of statutory overcrowding. However, many local authorities use a bedroom standard when assessing whether an applicant is overcrowded for the purposes of determining whether s/he has a reasonable preference under their allocation schemes for social housing.
The Allocations Code of Guidance recommends that the following 'bedroom standard' is adopted as a minimum measure of overcrowding, ie a one bedroom for:
each adult couple
any other adult aged 21 or over
two adolescents of the same sex aged 10 to 20
two children regardless of sex under the age of 10.
The LHA calculator is used for calculating housing costs you would be entitled to in the private sector-which is different to how many rooms the local authority say you need.
You need to google your local council allocation policy as that will tell you what their definition of overcrowding is.
Your son at uni should still be included in the calculation.
So for "over crowding" purposes the council would offer you
a 2 bed + living room ifyou are looking at a council property or if your allocations policy is more generous 3 bedrooms.
If you were renting in the private sector the LHA calculation says you would be entitled to the 4 bed rate of housing benefit/UC (it doesn't mean you need a 4 bed)
If you were renting a 3 bed in the private sector you would only get the 3 bed rate.
You're getting confused between the two (not unsuprisingly as it can be complicated)
Are you trying to work out how many bedrooms you are entitled to in a council property or how much HB/UC you would receive?
I can clarify it for you if you like.