Actually reg post is for smaller items, parcel for larger ones. And if the item (not documents; something like a small parcel) is from 1-2kg, u can opt for parcel post cost it will be cheaper than reg post. Parcel=RM3.50 and reg post=RM6.00 (excluding the sticker price). I know because i always use this 2 services. N fyi, poslaju cannot delivery liquid items as it's by air (sometimes can if the operator don't ask what is inside the box). I also wonder how u get the price RM2.50 for reg post but for parcel it's RM5.20.. It shudn't be..
To get the better rates, u just need to weigh the item n compare the rates at the website cos for small packets, u can always choose either reg post or parcel. =)

See here : http://www.pos.com.my/v1/tariff/OrdinaryDelivery.htm

To Singapore, it will take around 7 working days. You can use reg post if the item is small. Cost is based on weight so u can check it at http://www.pos.com.my/V1/main2.asp?c=/v1/t...mail/letter.asp. Do note that this price has not includes the reg post sticker yet.

Hope this reply is not too late