DETROIT/KOKOMO, Ind. (Reuters) – The latest proposed four-year contract for Fiat Chrysler Automobiles NV’s U.S. unionized workers would over time eliminate the much-maligned two-tier pay structure, allowing new hires to reach top pay within eight years, sources said. The proposal agreed by United Auto Workers and Fiat Chrysler (FCAU.N) (FCHA.MI) negotiators late Wednesday night would also increase the top pay for some second-tier workers to $29 in the course of the agreement, up from their current pay of about $19 per hour, sources said.