I can't speak to this specific type of slot but progressives are normally considered marketing tools.
When the progressive is won the money is written off by the casino as a marketing cost, not as a win.
Classically 0.00125 of each dollar contributes to a progressive.
That's 1.25cents for every $10 pumped into the machine.
The machine does not register this - as the progressive is basically incremented by the closing of a circuit - and is completely separate from the rest of the accounting.
The casino can change the percentage contributed at will - but Nevada gaming law won't let a progressive be retired - it has to move to a different machine or paid out.
MGM once had a slot with a progressive and a 24/7 web cam on it. People lined around the block to try their luck It had been accumulating for 25+ years.
On my personal slots I have bumped that up the contribution to 4% so I get 1c for every quarter (token) I put in.
- that way I know the progressive is working as I don't trust my own wiring.
Atypically if the top award (replaced with a progressive amount) is normally 1199 coins (note they use coins vs any $$ denomination) the progressive jackpot (base amount) is started at $1199 (assuming a dollar machine). The 1199 would register on the meter as the win (coin out). If the base jackpot is greater than the max win on a slot, the casino would usually have this insured by a third party. Ie 100k on the progressive would be insured by Lloyds of London and cost around $250/mth for the insurance - the casino would then deduct this $250 as a marketing cost as well.
Why 1199 coins - first off coins vs $$ makes the slot glass universal vs the denomination. Secondly a win of $1200 requires the US based casino to issue a W2G form and enforce tax reporting and for foreign folks (like us Canadians) a 25% withholding on the win.
In Canada neither Casino nor lottery wins are taxable under the argument that you played with after tax money, you get paid in after tax money.