Shapechange prc "The Dispassionate watcher of Chronepsis"

[ddude987]

     Rule as Written, if I qualify normally for The Dispassionate Watcher of Chronepsis (Draconomicon pg 89) and then I shapechange into a dragon (please assume shapechange grants spellcasting, I don't want to debate it and my DM ruled it does) and gain the dragons sorcerer casting levels.  I then Prestige into the noted prestige class and give up all the sorcerer levels the dragon granted in exchange for divine levels which I use to pump my Cleric spellcasting, when Shapechange runs out do I keep the divine spellcasting? 
     I asked multiple people and also another forum board and everyone gives a different answer... My DM said if I can give a good reason for why by RAW it works then I can do it.  Thanks so much! I know MinMax will know the answer.

[Vampireshado]

If I recall correctly the prc says you lose your sorcerer spell casting correct? So it's gone completely and you now have nothing to lose when your shape change ends. You then gain completely new spellcasting. So it's not like your new divine spellcasting is being sustained by your old sorcerer spellcasting. It's something completely new and permanent. By RAW it works. Now I assume this is in a very high-powered campaign or that big jump in casting is going to be stupidly unbalancing.

[awaken_D_M_golem]

Yeah but, when Shapechange runs out, you no longer
qualify for the PrC, so you lose most or almost all of the
PrCs abilities.  You still have Hit Dice, which retains a bit.

Generally there's minor handwaving on PrC requirements.
Keeping a Shapechange up and running is not "minor".

[Vampireshado]

That's a good point, if losing requirements does in fact cause you to lose the abilities of that class. Can I get a text reference on that? Not that I don't believe you I'd just like to be able to read it and show it to other people that ask.

Aren't there prcs that disqualify you by taking levels in the class?

[snakeman830]

Only one I can think of is Dragon Disciple, though that is only with the capstone.

[Maat Mons]

He said he intends to qualify independently of shapechange (probably as a dragonwrought kobold), so losing the class features isn't an issue. 

Another thing I notice is that aging adds extra levels of casting, but becoming younger doesn't take them away.  There's a use of bestow curse that ages the target (Book of Vile Darkness, p28).  While a dragon, you could repeatedly be subject to bestow curse and remove curse to yo-yo between two age categories.  Advance to ancient, gain +2 levels of cleric casting, advance to ancient again, gain another +2 levels of cleric casting, et cetera. 

Can I get a text reference on that?

The only reference I know of is Complete Warrior, page 16.  I'm told that the 2012 printing of the Dungeon Master's Guide added the rule that prestige classes don't count for multiclass xp penalties.  (That rule had not previously been in any 3.5 book.)  Maybe they added something on this too.