The following excerpts were written by educated natives:
Matthew Smith was a part of my business management team for two years, performing the role of Account Executive.
During which time, I found Matthew to be a valuable member of the team.
1) Shouldn't this be one sentence? 'during which time' is a relative clause is it not?
It was my pleasure to work with Matthew when he reported to me in the role of Account executive helping me manage the key accounts.
2) Shouldn't there be a comma preceding the ing clause beginning at 'helping'?
(P.s. I'm not trying to sound like a no-all, nor some pedantic writer who thinks he makes no mistakes of his own

)
Thanks