That's not a compulsory field. I guess it's not really matter.

Frankly speaking that I have been filling with wrong employer number for the past two years and I just realized that mistake this year.

Number 3, as below:
Subsidised interest for housing, education or car loan is fully exempted from tax if the total amount of loan taken in aggregate does not exceed RM300,000. If the total amount of loan exceeds RM300,000, the amount of subsidized interest to be exempted from tax is limited in accordance with the following formula:

An amount limited to a maximum of RM10,000 is deductible for each basis year for a period of three consecutive years of assessment beginning from the date in which the interest is first expended.
Conditions for eligibility:
(i) an individual who is a citizen and resident;
(ii) the purchase of the residential property is limited to one unit only;
(iii) the Sale and Purchase Agreement has been executed from 10 March 2009 to 31 December 2010; and
(iv) that residential property must not be rented out
Where:
(a) 2 or more individuals are each entitled to claim deduction in respect of the same residential property; and
(b) the total amount of interest expended by those individuals exceed