Letter of Credit Forum

I'm preparing the CDCS exam for following APR.

I have taken a CDCS practice test which is povided from www.cdcs.org, then I got complicated from first question lol

 The question is as below:

A documentary credit for USD 120,000 calls for shipment of feriliser in FEB, MAR, APR and MAY. Each shipment is to be for ABOUT 500 tonnes. Shipment was effected as follows:

1. 450 tonnes sent 24 FEB for value USD 27,000

2. 550 tonnes sent 12 APR for value USD 33,000

3.460 tonnes sent 30 APR for value USD 28,000

4. 550 tonnes sent 04 JUN for value USD 33,000

Which of the above shipments will be honoured on presentation?

and an answer is 1 only.

I could find out some evidence from the question.

First, This documenty credit is allowed PARTIAL SHIPMENT. Second, uses the word 'about' in connection with the amount that means the credit allows a tolerance not to exceed 10% more or 10% less than the amount, the quality or the unit price to which they refer.

So, I thought that example 4 is wrong, because the shipment is later that required period. also exaple 2 is wrong, because of according to USP 600, article 30 : Even  when partial shipments are not tolerance NOT TO EXCEED 5% less than the amount of the credit is allowed. Meanwhile, example 2 exceeds the amount of the credit, the amount of credit is supposed to be less than 30,000[USD120,000 /4(4months partial shipment)]. Consequently, I choose 1 and 3 only. But the CDCS.org's answer is 1 only.

 Why.............WHY!!!!!!!!!!!!!!!!!!!!!!!!!

Example 3 cannot be honoured????

Please guys...help me to settle my curiosity.

 I appreciate it in advance.

 Best regards,

Daniel Gim.