Because your three price levels for your conditional pricing table are: -40%, average price, and +40% you could do a fine job capturing it as -1 0 and +1 for the three values to be associated (within the estimation design matrix) with those three levels. Or, -2, 0, +2, etc.
You could also use 0.6, 1.0, and 1.4. Any of these ways, you're dealing with values in the single digits (best for convergence in CBC/HB) and also that the middle price is equidistant from the ends (because that's the pattern you put in your conditional pricing table).
If you are going to be building your own simulator, just make sure you remember that CBC/HB automatically zero-centers whatever values you use during estimation. So, the low price will be associated with a negative "price value" times the utility coefficient.
If you are using our SMRT or Online Market Simulators, if you select the option within those systems to look at your conditional pricing table, then you can just type the original prices in the simulation specifications (e.g. 3690), and the software will map that value to the appropriate value index per the conditional pricing table. This makes it easy to use the simulator in the end, because of that mapping, and allows you to specify products on the original price scale.
