Sub agent tour operator

I am a Travel agent in Mumbai. If I purchase a Europe package of Rs.10 lakhs for a family from our supplier in India I will have to pay 5% gst to package tour supplier on entire package ie. Total Rs.10,50,000/- including 5% GST, but when I sell this same package to my client will I have to charge GST from my passenger once again on the entier package amount ie.- 10,50,000/- + 25000 my service charge = 10,75,000/- x GST 5% ( Rs.53,750/- ) = Rs.1128750/- If this is correct then in that case Passenger is the sufferer because he ends up paying more then the double GSt. to goverment ie Rs.50,000/- charged by my supplier and once again I took GST on complete package including my service charge Rs.53,750/- Total double GST WILL BE COLLECTED FROM PASSENGER RS.50,000/- + 53,750/- = Rs.1,03,750/- only gst amount. is it correct please clarify. It sounds absurd. What I personally feel that I should take GST of 18% on my service charges only and not on entier amount. ie I should charge Rs.10,50,000/- ( this includes 5% GST charged by my supplier) + my service charges Rs.25,000/- + Gst on 25K ( 18%) Rs.4,500/- Total to collect from passenger Rs.10,79,500/- Please revert immediately as one of my booking is on hold I am not aware how much GST I should collect.