Yes, it is part of the HLE, and it's up to you to declare. (whether they check or not, nobody knows, but try not to test the system)
And some may be even asked to furnish credit bureau report.
Different criteria for different category of people.
If you need more loan, declare all transport allowance etc
Circle the final amount you want to declare on each month payslip (use pencil, do it before u scan), so the person reading it wont have to figure out exactly how much should your monthly salary be.
Of course if your salary + allowance is over the limit, then maybe circle the part which is permissible under current rule , and hope for the best.
vinz