What was the extent of Lavan's efforts to gain at Yakov's expense?
Ramban #1: Following the initial agreement, that Yakov would receive the spotted and blotched sheep and goats and the reddish-brown goats, he began changing the conditions annually, when he saw the extent of Yakov's successes.
Ramban #2: It may well be that he took to change the conditions after the sheep were already pregnant 1 - but to no avail. Hashem took into account Lavan's new conditions and formed the seed inside the mothers in Yakov's favor.
Hence the Pasuk says "Im Koh Yomar", in the future.
Why did the Mal'ah say "Im Koh Yomar" in the future?
Ramban: Because Hashem formed the lambs that would be formed each year in advance of the new conditions that Lavan set - after the sheep were already pregnant.
How could Lavan say "your wage will be the dotted ones"? They already agreed that Yakov gets the dotted and blotched!
Moshav Zekenim: Yakov stipulated that Lavan may choose each year to give to him dotted, blotched or Akudim.