Dose - Question on Mechanics of XR and IR

[designfactor]

As we all know, Adderall IR is designed to release all of the drug at once, in an average of a 4 hour high for most.

This means taking 30 mg IR is equal to taking 30 mg IR at once. (Duh)

Then we have Adderall XR, where half of the drug is released at once and the other half is released 4-5 hours later, resulting in an average length of 7-10 hours

This means that taking 30 mg XR is equal to taking 15 mg IR, waiting 4ish hours then taking 15 more IR

So in essence, 30 mg's of XR is only half as strong as 30 mg's of IR but lasts twice as long.

So SWIM's question is: Is the inverse of the above statement true? IR is twice as strong as XR but lasts half the time.

In other words, if SWIM has been taking only XR so far, but decided to convert them to IR, would this be the equivalent of taking twice as much XR but having the high cut short?

If SWIM's usual dosage is 30 mg's of XR, would he feel like he ate 60 XR if he was to convert the 30 XR into IR? But in return he'd only feel the "60 mg's" for half the time.

Or does it work so that converting XR to IR just skews the strength and time so that it's less predictable than SWIM is making it out to be?

(Sorry about the complicated wording for such a simple question...)