Writing ICC profiles capbilities: can we save modified tags or is it limited to saving header only?

I am thinking about "editing" CMYK output profiles with Matlab.

As you know, an output profile starts with a series of 'device' values (CMYK, in this case) and their corresponding 'device-independent' values. It could be CIE 1931/2 XYZ or CIE 1976 Lab. If I can 'open' an Output ICC profile A2B1 tag, for example, (Device to PCS), as a cform, I guess I could find a way to extract the XYZ/Lab colors to a new Matrix. Seems trivial. But, I don't suppose there are ny functions to write back the 'edited' XYZ/Lab data to the A2B0 tag and save the profile that way?

I know I'm pushing my luck, here, and you might probably say, "Well, Roger, you're going to have to code this on your own". I don't know? I know it's not Christmas yet but it's worth asking. Other users may have already explored the possibility before and have some opinion to offer.

I was stuck with trying to edit and output profile, this morning, and been toying with the idea of where best to work on this? I have all the measurements that lead to the profile generation, so if could alter the measurements BEFORE turning the data into an output profile, I might just be able to achieve the same results as editing an output profile? Just to be clear, I'm only concerned with the 'reverse" direction of such a profile, the Device to PCS direction. Such that, if I look at CMYK (or RGB) image on screen, by having tampered with the original measuremernts, I end up with a "distorted" (but maybe useful) view of this image? Often, what happens is that, in proofing, for example, an output is made. But if I need to "replicate" this output on a similar device? Like another printer? I'll leave it at that and pursue my own research, in case I come across anything interesting. I'm sure I'm the only Matlab user ever in its history to investigate such an interesting area.. ("interesting" to me, I know)