Improve scheduling granularity

Problem

Currently there is no daily scheduling within Scrum sprints or hourly schedule within Kanban projects.

Portfolio tries to solve a scheduling problem involving humans in a domain where stories are known to be difficult to estimate.
When the story estimates are precise and stories are dependent on the results of previous stories in a sequential manner, Portfolio is not able to schedule accurately.

If on a Kanban project, short dependent stories that are meant to be sequential, they can be either scheduled concurrently (if resources are available) or on different days.
In Scrum projects, dependent stories will either be scheduled concurrently (if resources are available) or on different sprints. There is no sub-sprint granularity.

As an scheduler, I'd like stories with dependencies to be scheduled after the completion of the blocking story but in the same sprint or day if resources permit.

Configuration Examples:

When using Portfolio in Scrum mode:

• With Dependent Story Constraint switched on, dependant stories can't be in the same sprint, even if they have a short duration.
• With Dependant Story Constraint switched off, the blocked story won't start before the dependant story but stories may be scheduled concurrently, so the dependant stories may be scheduled by Portfolio before the dependant story is complete and can actually be worked on.

When using Portfolio in Kanban mode:

• With Dependent Story Constraint switched on, dependant stories are scheduled the next day, disregarding the estimates. 3 dependent stories of 1h are scheduled in 3 different days.
• With Dependant Story Constraint switched off, dependent stories may be scheduled concurrently and 3 dependent stories of 6h scheduled in the same 8h day if resources allow.

The ON option doesn't allow for stories to be scheduled in a sequential manner with a granularity of hours.
The OFF option is expected to ignore story completion dependency.

Suggestion:

I'd like an option to enforce more granularity, so the schedule is done on an hourly basis for Kanban and daily basis for Scrum.
Alternatively: a configurable timespan (week or sprint) to calculate at a higher granularity.

Notes:

The time granularity is a linear factor in the complexity of the scheduling algorithm and increases will cause slowness when calculating the schedule.

Use cases:

• Sequential stories for operational Kanban teams. Some stories are done manually and others automated and normally short (1h). Estimates are precise.
• Scrum teams that have well planned dependencies that form a chain of concurrent stories that may or may not fit the sprint.