Finance Minister Nirmala Sitharaman on Tuesday said the GST council next month will discuss rationalisation of tax rates but a final decision on tweaking taxes and slabs will be taken later. She also said that compensation cess on luxury and sin goods are also going to be discussed and can come up in the September 9 meeting or later. The Group of Ministers (GoM) on rate rationalisation under Bihar Deputy Chief Minister Samrat Chaudhary met last week and broadly converged on retaining slabs under the Goods and Services Tax (GST) unchanged at 5, 12, 18 and 28 per cent. The panel also tasked the fitment committee -- a group of tax officers -- to analyse the implication of tinkering rates on some items and present them before the GST council. "The upcoming GST Council meeting will take up the issue of rate rationalisation. There will be a discussion on the issue. Committee of officers will make a presentation on rate rationalisation," Sitharaman told reporters here. However, a final .