Are following statements correct ?
1. Segment CTX Segment Context is required to be sent when IK304 is "I6" or "I9".
2. Segment CTX Element Context is required to be sent when IK403 is "I9" or "I13".
Yes, your statements are true, however, the use of the CTX is not defined by the code values as described, rather CTX is defined by the statements below:
From the 5010 standard: 1/0700
The CTX Segment shall be used to disambiguate a reported error that is dependent on context.