Energy transport in the Sun

1982, Robert Noyes, The Sun Our Star, says:

The energy released in (the core) as a gamma ray ... is destined to
spend the next 10 million years struggling to the surface.

BUT 2002, Freedman and Kauffmann, Universe, says:

As a result, it takes approximately 170,000 years for energy created
at the sun's centre to travel 696,000 km to the solar surface and
finally escape as sunlight.

Any thoughts on why this number has changed so radically in 20 years?
(Or if either or neither is right?)

--
Martin Frey
http://www.hadastro.org.uk
N 51 02 E 0 47