It's only shifting what year the government gets its revenue. The government should simply let the company choose how to do it, but if they choose anything other than year 1 interest will be payable at government bond rates.
It's also massively shifting the companies' cash flows. The company paid $X for R&D this year, but for tax purposes 80% of that $X expense is moved to next four years. So for this year's tax purposes, the company R&D expenses are much lower than what the company paid.
