spell questions

[Radiodada]

Hey, if I have a bard with 13 cha, and spend 1 AP to get the +1 cha enhancement, does that mean I can get rank 4 spells?
if I get a +cha item, can I access higher lvl spells if I put it on and flat keep it on?
if I hit lvl 11 with a cha of 13, and THEN get a cha to 14 with a tome about 1/2 way through, do i get access to 4th lvl spells next time I rest?

I'm trying to decide if I wanna buy a tome/if I should just use 3 ranks of the bard charisma ability(eventually dropping down to 1 or 2 ranks of cha and the capstone feat), or if I can just wear a +6 item.
I'm new to DDO, but not pnp dnd, and it's the differences between the rules that keep tripping me up

[whysper]

This one is similar to PnP, in that your current effective stat determines the level of spells you can cast. A 13 Cha and a +1 Cha item mean you are at 14 Cha, and able to cast 4th-level spells.

You should also be able to select your 4th-level spell when leveling up even if you do not have the requisite Cha at that time - just not able to cast it until you do.