We already had one rabbi paskening that one cannot divide up a purchase into multiple purchases in order to benefit extra times from the 4nis rebate given by Yesh.

Someone asked the same question, witha slight twist, to Rav Yitzchak Zilbershtein, rav of Ramat Elchonon in Bnei Braq.

The question posed to Rav Zilbershtein was: This fellow was in Yesh and saw someone in the self-checkout lane processing his items and after every 25nis he would sop and pay and then continue. He says he asked the fellow what's going on and the fellow explained that because Yesh was sued and has to pay out 8 million shekel, they are giving 4nis back on every purchase over 25nis. So, he says, I have a 400nis purchase here and am breaking it up every 25nis. So, on a 400nis purchase, I am getting back 64nis, this fellow explains. He says sure it takes a few more minutes, but it is worth my time.

So, the questioner poses the question to Rav Zilbershtein:
1. I want to do this as well - am I allowed to? They are only giving the money because they were sued, not because they want to. Perhaps one is not really halachically allowed to take this money at all!
2. can one break up the purchase and cause delays to other shoppers waiting in line?
3. He says he heard the branch owner say that one is not allowed to divide up a purchase to benefit extra - does he have a right to decide that?

Rav Zilbershtein answered that one is allowed to divide up his purchase and benefit multiple times from the rebate. If possible, the chain administration/owner should be asked what his intention was when he came to the agreement - did he intend to distribute the money to as many customers as possible, or did he just want to dismiss the suit as quickly (and as cheaply?) as possible. If he does not clarify or does not know, one is allowed to break it up.
source: Kikar

Rav Zilbershtein does not need my support, but his opinion makes more sense to me than the opinion brought earlier of Rabbi Kanner.