I guessed during last week the voucher will costs around 4$ just the same price as the packs.
Very possibly!, But I won't have to buy them then either, or all the way down. The challenge with waiting is if there is high scarcity and people are looking to complete their quotas, they might go higher. The volumes I am buying and selling aren't huge, but they do get me in the door :)
Even if the SPS price going to dip to half or third, and the same 'll happen to the vouchers its still cheaper to buy the packs during the upcoming weeks.
Yes, but if I can sell some SPS early and buy it back at half in the mid presale, I can power it up and earn more vouchers too.
At the end of the day, I think it will work out about even for me, but it means I don't have to worry about it.