Calculating childcare for TC

[TooMuchJD]

Think I already know the answer but totally paranoid about anything relating to TC's.

I work term time & pay childcare (B&A school) term time only. I have worked it out as £90x39/52 = £67.50 which I rounded up to £68. Our claim from last year was £73 per month and I went to the online checker which said I didn't need to notify them as it was less than £10 difference.

Have I worked this out correctly and am I just stressing for nothing?

There's 38 weeks of school per year.

I worked it as 52-13 weeks hols = 39 weeks ???/

There's five inset days which adds up to the extra week.

Of course, that would still be less than £10.00 change though.
Thanks NickNacks

Calculated childcare per week, and then said last year was 73/month. Are both numbers over the same timescale?

GreenSand Yes, they are both 38/52. Just realised I put month when I meant week