the end result is exactly the same with different speeds at which they dump and exit. as IEOs are already supported by and listed on an exchange they can dump and run away faster.
You got it absolutely correct. The only difference is that C and E in between. Otherwise, they are both the same bananas. They are actually both coin offerings, the other one offered to the open public from the project itself while the other one is offered through the exchanges. There are tinier differences such as ICO coins might not be listed at all while IEO coins are going to be listed immediately right after the offering, ICOs are offered in an absolutely free market where a scam is offered alongside a much lesser scam while IEOs are somehow screened by a third party which is the exchange, and so forth. But all these differences could really be insignificant.
You just put out the basic difference. ICOs are fund raising campaigns organised by the developers of the project itself, they have full control of the funds. IEOs are organised by the exchange and they have initial funds control. Asides this, the result which is "loss" is usually the case for investors when they allow complacency to kick in. Nothing different in that regards