Long time lurker, first time poster... be gentle :-)

Before the sale ended, I was pricing out a LHR/JFK return with my Corp. Travel Agent.

As usual, I went for the no-changes/no-refunds "I" fare for approx. £2000, but the TA asked if I needed any flexibility and told me it would be £5,774 for a "semi-flexible" ticket. She didn't mention the bucket, but ITA matrix would have me believe she offering me a "C" fare.

Question:
- ITA matrix said that a return in R each way would be around £4,000 (and there was even an LCY/JFK fare in R for ~£3,500.) I understand that R is "less flexible" than C in that there's more likely to be C availability than R for a given flight, but is there anything else about R fares that I don't know that meant the TA only offered a C fare? (The fare rules seem very similar - basically £200/change + difference in fare.)

- ITA matrix also said that I could have a return in A (First) for £3,200 (even cheaper than R (Club World)). This fare also seemed to have similar flexibility conditions as the R and C, but with the added benefits of First. If I had needed flexibility, is there any reason not to have gone for the A ticket?