Traverser Stones not granting correct Visitant Time

[Edwardteach]

Name: Traverser Stones not granting correct Visitant Time

Platform: Windows
ISP: Comcast/Xfinity
Type of Internet Connection: Cable
Internet Connection Speed: 15Mbps
Date & Time: April 5, 2104 10:00am
Frequency: Once (did not reproduce)
Character Name: Edwardteach
Race: Galka
World: Levithian
Main Job: Puppetmaster 88
Support Job: Dencer
Area and Coordinates: Abyssea - Grauberg (entrance)
Party or Solo: Solo
NPC Name: Conflux Surveyor
Monster Name: N/A
Steps:

I entered Abyessa - Grauberg today and attemped to extend my Vistant Time by exchanging Traverser Stones to the NPC through the chat options. My options were
1 - 30 mins
2 - 60 mins
3 - 120 mins

I selected 3. The Conflux Surveyor then stated that I would be granted an additional 36 mins of status from my ancient abyssites. I selected ok and my text log showed this:

You expend 3 traverser stones.
Your visitant status has been extended by 61 minuets.
Your visitant status will wear off in 81 minuets.

Shouldn't my Visitant status have been maxed out at 120 mins? Where did 61 come from? What sort of math is involved there?

Here is a pic of the text log: