Staff Nexus staff upgrade

[Bipeo]

The Staff Nexus arcane thesis says that you can upgrade your makeshift staff to any other type of staff by spending the appropriate cost and then it gains the two spells you chose in the beginning.

Does the staff it turns into gain charges normally for the type of staff it is? and can you upgrade that one later to bring your chosen spells along?

Or is it that once you upgrade it, that's it and once you get a higher level staff the first one is just obsolete?

[Ravingdork]

I'm of the opinion that it is a normal spell staff in all ways, except that it possesses additional spells and can produce additional charges.

[Bipeo]

But would you then be later upgrade it again when you get higher level?

Say I have my makeshift staff with:
Cantrip Ray of Frost
1st Animate dead

and I turn it into a staff of necromancy. now it has
Cantrip chill touch, ray of frost
1st grim tendrils, ray of enfeeblement, animate dead
2nd deafness, gentle repose

Can I later turn that into a greater staff of necromancy to have
Cantrip chill touch, ray of frost
1st grim tendrils, ray of enfeeblement, animate dead
2nd deafness, gentle repose
3rd blindness, vampiric touch
4th grim tendrils, vampiric touch

Or am I stuck with needing to find a separate greater staff on necromancy that just has

Cantrip chill touch
1st grim tendrils, ray of enfeeblement
2nd deafness, gentle repose
3rd blindness, vampiric touch
4th grim tendrils, vampiric touch

and my old staff is just obsolete and I don't get to use animate dead and ray of frost anymore?

[Ravingdork]

Insofar as Im aware, you can upgrade items by simply paying the difference.

[OilyTrout]

Bipeo wrote:

But would you then be later upgrade it again when you get higher level?

Say I have my makeshift staff with:
Cantrip Ray of Frost
1st Animate dead

and I turn it into a staff of necromancy. now it has
Cantrip chill touch, ray of frost
1st grim tendrils, ray of enfeeblement, animate dead
2nd deafness, gentle repose

Can I later turn that into a greater staff of necromancy to have
Cantrip chill touch, ray of frost
1st grim tendrils, ray of enfeeblement, animate dead
2nd deafness, gentle repose
3rd blindness, vampiric touch
4th grim tendrils, vampiric touch

Or am I stuck with needing to find a separate greater staff on necromancy that just has

Cantrip chill touch
1st grim tendrils, ray of enfeeblement
2nd deafness, gentle repose
3rd blindness, vampiric touch
4th grim tendrils, vampiric touch

and my old staff is just obsolete and I don't get to use animate dead and ray of frost anymore?

thank you for your question :)