Why the pay gap between varsity and polytechnic scholars?

I REFER to the advertisements displayed in SMRT trains pertaining to the Joint SAF Scholarship Scheme open to university, polytechnic and Institute of Technical Education (ITE) applicants.

The advertisements state that the starting salary for graduates of the National University of Singapore, Nanyang Technological University and Singapore Management University is up to $3,740 per month and applicants would be offered promotion to the rank of captain within one year of graduation.

On the other hand, the starting pay for polytechnic and ITE graduates is up to $2,162 and $1,991, respectively. Both would be offered the rank of third sergeant upon graduation.

How is it that there is such a large discrepancy in starting pay between graduates of the universities and the polytechnics, given that both are classified as tertiary institutions?

Also, why do polytechnic and ITE graduates start with the same military rank?

It is an irony that the starting pay of polytechnic graduates is only marginally higher than that of ITE graduates and lags very much behind university graduates'.

Perhaps the Singapore Armed Forces could enlighten us on this issue.