The results of the company's cost-cutting measures
are evident in its profits, which increased 5 percent
during the first 3 months of this year after it fell over
the last two years.
(A) which increased 5 percent during the first
3 months of this year after it fell
(B) which had increased 5 percent during the first
3 months of this year after it had fallen
(C) which have increased 5 percent during the first
3 months of this year after falling
(D) with a 5 percent increase during the first
3 months of this year after falling
(E) with a 5 percent increase during the first
3 months of this year after having fallen


OA is C, but my doubt is related to tense issue in option A.
OG Mentions that A is wrong for two reasons
First, it is ambiguous.
Second,tense usage is wrong as sequence of events is unclear. Sentence Requires present perfect.

I understood the first reason, but i have some confusion related to second one.
Since "After" clearly defines the sequence of events, i think usage of present perfect is unnecessary.
I have read this rule in Manhattan SC book.

Experts please clarify why present perfect is required even if AFTER is used in sentence.