MA (F2) Mock Exam Question- High/Low

Hi John,

This question relates to the F2 Mock Exam re High/Low:

‘Berry has recorded the following costs over the last six month:
Month 1 2 3 4 5 6
Units Produced 3,000 1750 2,000 2,500 1,500 2,000
Total Costs £74,000 £72,750 £73,250 £75,000 £69,500 £72,750

Using the High-Low method, what would be the total cost equation?’

I had answered the question by doing 75,000-69,500/3,000-1,500= £3.66 per unit- reason for this is that £75,000 is the highest cost and £69,500 the lowest etc

The answer is saying that i should of done £74,000-69,000: i’m confused by this because £75,000 is higher than £74,000, is there something i’ve missed here?