Fall in GP rate - increase in cost of purchase - 95% of sales...

Fall in GP rate - increase in cost of purchase - 95% of sales were made to related parties - Since no explanation was offered by the assessee before the AO regarding fall in GP rate AO has not estimated the income by totally disregarding the book results and he has only made an estimated addition because the assessee could not explain the reasons behind fall in GP rate particularly when the major sales to the extent of 95% are to the related parties