Ours are well overestimated in that - all the prices listed are for new season ticket holders who missed the early bird rate in the most expensive stand. Most adults will have paid less than £300 and concessions less than £200.
Most clubs will do the same won't they, but if it listed every discount it wouldn't be a very good graphic or at least over complicated. So doing the actual price seems the best idea.
We have discounts for both last season's ticket holders and the years before ( because most didn't renew last season due to no fans likely)