Do Evaluations for "Draft Experts" Change Too Quickly?

Internally, we had a discussion among some of the SB Nation football contributors involving whether the draft projections for someone like Mel Kiper Jr. fluctuated too much throughout an offseason. To summarize, here were the arguments for and against changing evaluations on players:

Why Draft Rankings Should Change: Teams get a chance to interview players and see how they perform at the NFL Combine, their Pro Day, or individual workouts. Impressive numbers can elevate one player's stock over another player's stock.

Why Draft Rankings Shouldn't Change: In January, the major part of evaluations should be finished, based on everything that is on tape regarding a player. The only thing that should really change a ranking would be an injury or other unusual circumstance. Two workout days (NFL Combine and Pro Day) should not be enough to change a player's stock from the first round to the second round, or vice versa.

Primary Examples: SB Nation's Kenny Stein did a comparison of Mel Kiper's first mock draft compared to his fourth mock draft that was released last week. Here are some of the startling differences:

Big Fallers

• DE Damontre Moore - From No. 2 overall to No. 58 overall (drop of 56 spots)
• DE Bjoern Werner - From No. 6 overall to No. 36 overall (drop of 30 spots)
• DT Johnathan Hankins - From No. 15 overall to No. 56 overall (drop of 41 spots)
• RB Montee Ball - From No. 21 overall to No. 46 overall (drop of 25 spots)
• DT John Jenkins - From No. 25 overall to No. 57 overall (drop of 32 spots)
• DE Sam Montgomery - From No. 20 overall to not being in the first two rounds

Big Risers

• OLB Ezekiel Ansah - From No. 17 overall to No. 2 overall (gain of 15 spots)
• DT Sharrif Floyd - From No. 30 overall to No. 3 overall (gain of 27 spots)
• QB Geno Smith - From not being listed to No. 4 overall
• OT Lane Johnson - From not being listed to No. 11 overall
• WR Tavon Austin - From not being listed to No. 16 overall

There were other examples, too, but I think the question I am trying to get across should be clear enough now. I'm not saying that Kiper did not get things right in his most recent mock draft, but which side are you on? Do you think the so-called "draft experts" should be allowed to change their rankings so drastically on so many players over the span of a couple of months, or should they be more consistent and stable with their analysis throughout the entire process?