i agree that those in the shopping centre charged more for their work but who can blame them? one need rental while the other don't, that said, there is a difference in term of material quality.
not all, some at the shopping centres/malls provide very good service and quality.
Use to go to the one at the basement of Junction 8. Good and friendly service. good skill and quality.
got 2 or 3 within 200m of one another at hougang central (opp HG mrt)
HG Ave 8 Blk 683 near 24 hour indian muslim kopishop.