New Bass String - Eye Unwinding.

[John Ross]

Hi List,
I just replaced a set of bass strings, on a 1948 Heintzman, apartment size
piano.
The customer did not want the bass strings, rescaled.
The top six strings had a problem, of the pitch dropping, drastically. It
was the eye slipping.
I contacted the vendor, who is replacing them at no charge.
His explanation was that these strings were scaled to 60% of their breaking
strength.
My thinking is that the only problem that should be caused by that, would be
the string breaking, or the tone different. Apparently the strings below it
were at 45% of their breaking point.
What is the consensus, on the reason for the eye slipping?
Thank you.
Regards,
John M. Ross
Windsor, Nova Scotia.
jrpiano@win.eastlink.ca