Loading charges / conveyance

Sir, I am GST registered dealer/trader and am supplying goods to another GST registered company in the same state via a TRANSPORTER on TOPAY BASIS. I have to raise a TAX INVOICE for two products and
(a)the tax for the first product is 18%
(b) the tax for the first product is 5%
The total TAXABLE VALUE is 18000/-

question 1: A two wheeler is used to carry goods by my staff and my staff does the LOADING part and the goods are handed over to transporter, and a LR / Way bill receipt is issued by transporter to us. I would like to add LOADING CHARGES, say Rs.100/-. Would I need to charge TAX, if so would it be 5% or 18% on TAXABLE VALUE.

Question 2: If the same goods are transported via a four wheeler from a unregistered service provider and if the goods are LOADED by the UNREGISTERED SERVICE PROVIDER wherein he collects 500/- as COOLY for LOADING, how this amount should be raised in TAX INVOICE, since I would need to collect the amount from the RECEIPIENT of goods.

question 3: Are there any implications or rules for the charges depending on the TAXABLE VALUE. i.e if TAXABLE VALUE is less than AMOUNT A, else etc.

Kindly advise.