Putting on my mathlete hat, I can tell you confidently that if some combos are paying too low, then there must be others on the flip side. Let's do an example:
Gross pool: $5,000
Net pool: $3,800
That represents 1,900 $2 tickets.
Let's assume that everyone knows the percentages, and bets are made in proportion to the expected combo's liklihood. See Craig G tables at Jai-Alai Heaven.
Take a most likely (142 or 241) and a not very likely (156 or 256), and run the numbers. Here's what you get:
Combo 142 156 (same as 241) (same as 256) Probability 0.0093434 0.0009058 1 chance in ??? 107 1,104 Net Pool 3,800 3,800 $ Bet (net) 35.50 3.44 Payoff $214.05 $2,207.99
Here are the last 10 1-2-4 payoffs at Dania:
The average is $184. We haven't even considered who is in those
Now, does that mean there is manipulation? $184 instead of $214. No, it only means that people are backing the 1-2-4 a bit more than its expectation would justify.
The people, you say? Yes, Jay, JS and Jim. YOU is the people, and YOU is makin' the odds.