ETDRS visual acuity - a puzzle

Here's something that is foxing me presently..

When papers/guidelines discuss the ETDRS chart and visual acuity, for example VA cutoffs for IVT, the number of letters quoted always seems too high. Is there an ETDRS chart I am not aware of?

Every ETDRS chart I have seen has 70 letters: 14 rows of 5 letters.

But, for example, the SMC guidance on treating DMO says: "treatment of visual impairment due to DMO in adults with best corrected visual acuity (BCVA) 75 Early Treatment Diabetic Retinopathy Study (ETDRS) letters or less at baseline. "

75 letters or less? But of the chart only has 70 letters, that's everybody?!

I am confused...

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