Industrial Action - One Rule for One?

Just wondering if anybody can answer this question. We've received some documentation from the County on how to act next week with the strike (i.e. who should be at work, what the procedure for signing in is etc etc) and it states that teaching staff will lose 1/365th of their annual salary for each days strike they partake in - unless my maths is way out, this boils down to 1/7th of a weeks salary. Support staff will lose 1/5th of their weekly salary.

So, to simplify it, if me and a teacher both get paid £70 per week, and we both strike, the teacher will drop £10 from their wage for each day they strike, where as I would drop £14 for each day I strike.

1) Have I read this right?

2) Are my calculations correct?

3) If so, how is this fair?