History charts connect the same logical model across successive published quarters. You should expect a gentle downward slope as age increases each edition.
Flat segments can mean the model sat in the same age band. Steps may follow multiplier table updates or data corrections.
Always compare at the same specification. If history looks flat while single-quarter values moved, confirm you did not change filters between points.
Export or screenshot with the quarter visible for your files.
Reading price history across quarters
How to interpret a downward or stepped curve when browsing historical editions.