Backdating housing costs

Client claimed JSA online and was awarded Contributory JSA.  He should have got help towards housing costs 13 weeks later.  However housing costs weren’t included until he enquired and made a new claim for JSA IB.  He can’t remember whether the online application asked whether he had housing costs.  If it did and he ticked yes we can argue this should have generated a claim for JSA IB.  Does anyone know whether it does ask?  I haven’t seen a JSA claim form for years!  Any other ideas for backdating housing costs?  He has lost out on 4 months worth.