I don't know if every machine has different versions. But in my experience, those machines that do, often have different cells. For example there were 3 different Star Wars Cell Images. On my Yamato, the "heavy" version features Kodai/Yuki couple where mine "lite" features Dessla.

Also the different models often have information tabs on the cell itself that explains what model it is as well as the odds for that machine.

The "light" and "heavy" machines are usually setup to basically payout the same "statistically" .

For example, my Yamato machine has 1/99 odds for a bonus, vs the 1/310 odds for a bonus for the "heavy". However, the majority of my bonus consists of 10 ball payouts for 7 rounds at 8 payouts per round (560). The "heavy" machine has a payout of 13 ball payouts for 15 rounds at 9 balls per round (1755).

So while my odds are roughly 3 times greater, my payout is roughly 1/3. In the long run the machines should pay out roughly the same. It just means that the "lite" versions don't have the "big" wins that their "heavy" ones have.