you are not wrong, the commission these days is based on fee that the tutor charges.. of course the boss usually gets the biggest cut, and then the individual agents get a smaller percentage.
so when you think about it, it really depends.
for a person with deep pockets who seems clueless, naturally it is tempting for a tuition agent to serve up the tutor who charges a lot, with reasonable experience/qualifications behind it.
however, singapore parents are also very much singaporean, they want cheap things that are good. so you end up with parents asking for $15/hr and wanting MOE teachers to teach their kids. that is immensely ridiculous, if i am an MOE teacher who can command $50/hr upwards, why would i want to do that?
if you think about it this way - if i am an agent getting a 20% cut of whatever the agency gets (which is what i gather from some agents i spoke to), if monthly fee $150 versus $200, the difference is $5. but the difference of $50 is significant to parents, so i might want to move it faster and get a $150 tutor instead of a $200 which the parents might not want to accept.
that said, i think the way some agencies screen their tutors is quite scary.. they just take whatever the tutors claim at face value, without verification.