Ok, settled the issue and decided to share the contractor contact coz after getting 6 quotes, his price was the best. $160 to install 1 window worth of safety strip (regardless of number of panels). $60 more per window beyond the first. Average price out there is $180 - $220 for 1 window's worth. He's in the HDB list of approved contractors.
Kian Hong Aluminimum Works Pte Ltd
Tel: 6369 4812.