First of all, the Shakti engine that powers Dhruv and LCH would be to powerful for LUH, that's why Mod wanted Snecma to develop a smaller version of it, but they asked for to high costs. Secondly, we did had some parts in the development, but only a minor part because since then we hardly had any expertise and the engine is still based on the French predecessor.
The issue is not new design of small engine, they asked exorbitant price for designing a new transmission for using single engine shakthi.