You can always tell whether you're playing fixed or progressive rules by tapping the 'Territory Cards' button in the bottom right of the map screen.
- If you're playing fixed rules, the bonus values table will show '4 Infantry', '6 Cavalry', '8 Artillery', '10 All three'. In other words, the bonuses are fixed for certain card combinations.
- If you're playing progressive rules, you'll see a smaller table that will show numbers only, and the current trade-in bonus will circled.
Tapping the help '?' button on the cards screen will explain the Territory card trade-in bonus rules (for either fixed or progressive) in more detail.
To learn how to set the Territory card bonus rules when setting up a game, check this FAQ article.