OSTC4 not calculating Deco correctly. Possible Bug?

[Divert]

Hello, in the process of knowing my OSTC4 better I decided to plan a dive, first in Subsurface and then in OSTC4 to compare.
The dive:
50m depth with 60 minutes bottom time.
Algorithm VPM-B +3
Gas 1 Air
Gas2 NX50

Subsurface: 10 different Stops!

The OSTC Plan with same parameters:
Gases:

Settings1:

Settings 2:

[Divert]

Continuation....

OSTC Plan: ONLY 3 Stops!

I started the simulation to understand what would happen and some strange things started to happen: for example

No stop at 15m. Why???

On another run 40m with bottom time of 40 minutes The OSTC4 mandated a deco stop shallower than the calculated Ceiling!!!!

As I startet to get nervous, I switched to Bühlmann ZH-L16C and ran the 40m 40' simulation. where a full deco stop disappeared wile still on the bottom time!!! I took a video for you to watch the behavior. https://nube.buceoluegoexisto.com/s/GsbsiHG2imd4M2G

Please advice.

Humberto

[swissdiving]

I very much doubt therecis a bug. Diving the ostc4 for years now not having a problem with deco....

[Divert]

I very much doubt therecis a bug. Diving the ostc4 for years now not having a problem with deco....

This is so nice to hear! Do you dive also with VPM?

I am so willing to find that I am wrong about this. I love the computer and the support from Matthias and Ralph

[swissdiving]

VPM and Bühlmann.

[heinrichsweikamp]

Thanks for the detailed report, we'll have a look into this. There will be some improvements in the next releases with the VPM (The time for 9m is entered in the time for 6m and then overwritten for the list display) the total ascent time is correct, also the shown "next stop". A bug, yes: But not critical. We'll fix this.

regards,
Matthias

[Divert]

Thanks for the detailed report, we'll have a look into this. There will be some improvements in the next releases with the VPM (The time for 9m is entered in the time for 6m and then overwritten for the list display) the total ascent time is correct, also the shown "next stop". A bug, yes: But not critical. We'll fix this.

regards,
Matthias

Thanks @Matthias What about the disappearing Deco Stop @15m with Bühlmann ZHL-16C as shown in the linked video? Is that a bug on the Simulator or is it a problem with real decompression calculations on the OSTC4?

Please advice if it is safe to dive with.

Regards.

Humberto.

[Divert]

Thanks @Matthias What about the disappearing Deco Stop @15m with Bühlmann ZHL-16C as shown in the linked video? Is that a bug on the Simulator or is it a problem with real decompression calculations on the OSTC4?

Please advice if it is safe to dive with.

Regards.

Humberto.

Any word on this? @Matthias @Ralph ?