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

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.