We started a new campaign recently and decided to keep track of our progress using www.d2etracker.com. It is really a fancy and handy website, although I have a question. Once all heroes had 1XP, we all 'bought' 1 class card. The following quest was also won by the heroes. You'd say that, at that point, the heroes would have 2 XP to spend on class cards. But, in the d2etracker website, it tells you you have only 1XP to spend. Then we figured that the website calculates that you already spent 1XP on the first class card, and 2 - 1 = 1, so that makes sense. But I cannot find any way to tell the d2etracker website that you want to switch a class card (with a cost of 1 XP) for a class card that costs 2XP.

Does anyone know how to handle this?

I think it's because if you follow the rules (like www.d2etracker.com does) once you have bought a class card you can't exchange it (there are some powers / cards / rewards that specifically allow it).
So if a hero wants a 2XP card he must first 'keep' 1XP unused so the next time he will have 2XP available.

I already had a feeling that it could be something like that. So we've basicly house-ruled that unknowingly since the start?

Well in that case we'll just have to 'ignore' that aspect of d2etrakcer.com

Essentially what you want to do is not allowed by the rules. There are a few exceptions though:

- Play as "Arvel Worldwalker" and use her heroic feat (Shards of Everdark Expansion)

- Buy the "Archaic Scroll" trinket while transitioning to Act II and use it in one of the following quests (Shadows of Nerekhall expansion)

- Win the advanced quest "Crown of Destiny" and use the advanced quest reward "The Path not taken" (Crown of Destiny Expansions)

Every one does as he wants.. but doing like that you risk to favorise the heroes and it will be more difficult for the OL to win, indeed the heroes will always have the best powers!
Whereas the Campaigns are done taking into account that the heroes stay with the same powers during two or three quests in a row

You can do the same with the OL cards ... but I think it will less advantageous.

A last point.. but doing like this heroes will be able to pickup the best cards for the coming quest :

- it's a running quest let's take all powers that give mouvement points or some sort of teleportation,
- it's a fighting quest let's make the more damages

By RAW ok it's a running quest you have running powers ok you will probably win..
next quest is fighting : well you will be able to run ... for your life !! ;-P

I think the idea that you can exchange class cards after each quest comes from the fact that we played with the app at first.

Although I agree that it is against the RAW and can give the heroes an 'edge' (as Felin described; in a quest where a lot of movement is involved you can pick cards that improve movement, in a combat-intensive quest you'll pick cards that increase attack or defense...), but oviously the same goes for the OL, we agreed that after each quest the OL may also change the cards of his deck. I have just recently learned that this ís RAW.

On the note of OL cards, in the d2etracker.com website you have to provide with which deck the OL will play, in our case there are two possibilities: Basic, and Basic II. I assume that means that if you choose Basic II, you may not include cards from the Basic deck, correct? You may, however, 'buy' OL cards from the different classes even if they are originated from different expansions, correct? In that sense, what is the difference between a class OL card like a Warlord or Magus card, and Universal OL cards?

Yes by the rules Basic and Basic II are mutualy exclusive, and you can't mix both (even if I know of some people who house ruled with mixing them).

After choosing the Basic deck you can, after that, buy any cards you want.. but there are some rules !
You can only by a 2XP card from a class if you have already bought 2 1XP cards from the same class
You can only by a 3XP card from a class if you have already bought 3 cards from the same class (could be 3 1XP cards or 2 1XP + 1 2XP).
Universal can always be bought.

This leaves a few possibilities
-but mainly on one camapign you will be able to only by one 3XP card.. so better have a good idea of which one you want because you will need to buy many cards from this same class (at leasst for 3 or 4XP) in order to be able to buy this 3XP card.
So you are not doomed to buy cards from only one class .. but if you want a 3XP one you will at the end have only one or two cards from other classes / Universal

-another way that is also commonly used is to buy a lot of 1 XP cards from differents classes.. in theory you will have less powerfull cards but this allows more diversity to counter the heroes depending on the quest type.