The answer is, to prevent mis-operation and reverse effects. In fact, the Yagya which we perform are very large, effecient and powerful yagyas. If something  is powerful then incorrect use of it can be that much harmful too. Normally, people don’t have suffiecien knowledge about a Yagya but they always attempt to try. Trying is not bad if it is limited till devotion, but when it becomes a remedy, a trial can be dangerous too. The same happens with the so called pandits who are never educated but just doing this profession for bread butter. They will always get ready to do any Yagya without  thinking whether they know about the terminologies of Yagya or not. In fact, they either  won’t do Yagya or they will do that in incorret  way. So you have either no result or negative result but never a positive result. Keeping these things in mind, we have compiled these Yagyas in codes so that only our qualified Pandits can understand what the astrologers mean for you to be perfomed and what are the expectation for which the Yagyas should be modified.