i will highly recommend you to join Purushottam Sir . sir explains every concept in details and many teacher will not provide you the logic behind using a formula in costing but purushottam sir derives all the formula in class itself which makes it easy to remember them
For CA Inter & Final Costing you must go with Purushottam Agarwal Sir because he is the best faculty for this subject and he cover 100% Institute materials.
teaching technique is also exam oriented and sir provides many short tricks which will help you in exam. Also the best thing i liked about sir is points to remember which helps in revising in exam time.