[Scheme-reports] TAI epoch

In section 6.14, the description of current-second reads:

The value 0.0 represents midnight on January 1, 1970 TAI

(equivalent to ten seconds before midnight Universal Time)

However, according to the TAI-UTC table

( ftp://maia.usno.navy.mil/ser7/tai-utc.dat ),

it appears that TAI-UTC difference reached 10s

only after 1972. Here's the excerpt of the table:

 1966 JAN  1 =JD 2439126.5  TAI-UTC=   4.3131700 S + (MJD - 39126.) X 0.002592 S
 1968 FEB  1 =JD 2439887.5  TAI-UTC=   4.2131700 S + (MJD - 39126.) X 0.002592 S
 1972 JAN  1 =JD 2441317.5  TAI-UTC=  10.0       S + (MJD - 41317.) X 0.0      S
 1972 JUL  1 =JD 2441499.5  TAI-UTC=  11.0       S + (MJD - 41317.) X 0.0      S
 1973 JAN  1 =JD 2441683.5  TAI-UTC=  12.0       S + (MJD - 41317.) X 0.0      S

Before 1972 the formula is a bit involved, but January 1, 1970

is MJD 40587, and the TAI-UTC difference is about 8s.

I'm not very familiar in this field so it's likely that

I'm missing something.  Are there a reference I can look up

for the "ten seconds" explanation in R7RS?