BPP Revision Kit (Mock Exam September 2016)

Question 29. The direct labour cost per unit has been based on an expected learning rate of 90% but now the finance director has realised that a 95% learning rate should be applied. The answer: The target cost will remain the same and the cost gap will increase. My question: Why does the cost gap increase? Is it because a higher learning rate means they are learning more on the job? Learning more on the job means they are slower and less efficient, thus increases cost.