Question about the chart of pattern "Heart Double Knit Hot Pad"?

hello all,

In the chart of pattern “Heart Double Knit Hot Pad”, I have some questions and would you like to help me to solve it?
This is the link of the instruction of pattern

http://www.knittinghelp.com/patterns/free-knitting-patterns-heart-double-knit-hot-pad

and this is the chart of it.

In the instructions said that i need to cast on “60 strands/stitches to work on the next row.” because “Each square on the chart represents two sts, one facing you to k in the color shown and one not shown to be p in the color not shown.”, but i have been counted the row of chart and each row only have 29 squares, that means total we only need cast on 58 strands/stiches?
If we cast on 60 strands/stiches as the instruction of pattern, we will remain 2 another stiches and that so how come we do for them? and they will be stay at which position in the row of chart and knitting in what color ?

I am very interested with this chart and especially the double knitting, so i would like to know the way to do it. Please help me. Thanks a lot.

Yume, this has come up before. I don’t understand why they have you cast on 60 instead of 58. I think I would just cast on 58 and see if that works, I think it will.