Lets disregard what Rail For Less is showing on its website for a moment. Is it possible for Amtrak to drop a high bucket to a lower bucket for whatever reason, for one day or a few days? Has this ever happened? I check a certain trip twice a day, even though its 10 months out, I am hoping I may see a drop at some point.
We speak of "bucket drops", I do too, but it really is not an accurate way to think about how it works.
All the inventory on a given train is allocated across the bucket price points at any given time, even though only the lowest one having unsold inventory can be seen.
For example, current allocation of the 10 Bedrooms on the the 4/15 departure of 3 might be:
0 in 1st through 5th buckets
5 (known fact) @6th bucket, $2216/single adult
3 (speculation) @7th bucket, $2523/single adult
2 (speculation) @8th bucket, $2879/single adult.
"Bucket drops" happen for two basic reasons. The first is sales have moved into a higher bucket but then cancellations release inventory in lower buckets. In the case above, let's say a few months from now 5 Bedrooms have sold, consuming the entire $2216 inventory and now open inventory starts in the $2523 bucket. Someone cancels, so now there is one room open in the $2216 inventory. The price offered on the website will drop to $2216, a "bucket drop". The other reason is yield management decides that, having consulted the entrails of a goat, they need to reallocate inventory. Say, in December, four months prior to departure, time for some sales to have developed, none of the 5 rooms allocated to the $2216 inventory have yet sold. Yield managers decide to reallocate 2 of those rooms into the 5th, $1951 bucket to hopefully move them. So the price offered on the website drops to $1951, another "bucket drop".
Trying to find bucket drops of the second category, reallocation, is the whole point of this exercise, at least for me. I recently scored a 1st/low bucket roomette of $619 on the Builder for my November return from New York doing it. Prices on the Builder segment had been in, I think, like the 6th(980) or 7th (1227) bucket, but with at least 6 rooms open (this was before someone pointed out railsforless inventory feature to me). With that many rooms open, I had decided to sit tight, watch and wait. At 6 months out I started checking regularly for a reallocation/"bucket drop" and low and behold there was one. And a particularly good one, lowest bucket.
With no actual sales yet developed and 10 months to go until departure, the chances of Amtrak yield management feeling the need to go in and change their inventory allocation right now are slim to none, IMHO. For the time being, they've done their allocation and are happy with it. While yield management is "dynamic" pricing, day to day it isn't very dynamic.
Personally, I'll check occasionally, then at about the 6th month mark, I will start checking regularly, roughly daily. 4-6 months out is when I've found reallocation somewhat regularly happens for the trains I mostly ride. But whoever/whatever does the yield management for the Eagle and Chief seems much less active than those doing the Builder. Railsforless indicates pricing is a lot more static on those trains.
Short answer, bucket drops happen, but are not likely to at 10 months out.