Hi,
I am sorry but I don't understand your question or the code you wrote.
As the debug message is telling you, the variable $shipping_id contains an array with your data ; you got your shipping ids so I don't see any kind of problem (except that you want to display an array as a string so you got the PHP notice)
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.