Just did another quick test and the Mythic Tier does not seem to be increasing the save. Here is a Fighter 1 with all 10 Ability scores and Mythic Tier 1. The Fort Save is still listed as +2 even though the Mythic Tier tab shows it giving an additional +2.
Unnamed Hero
No Race Fighter 1 Mythic Tier (Champion) 1
Medium
Init +0;
Senses Perception +0
--------------------
Defense
--------------------
AC 10, touch 10, flat-footed 10
hp 15 (1d10)
Fort +2,
Ref +0,
Will +0
--------------------
Offense
--------------------
Speed 30 ft.
--------------------
Statistics
--------------------
Str 10,
Dex 10,
Con 10,
Int 10,
Wis 10,
Cha 10
Base Atk +1;
CMB +1;
CMD 11
Feats
Skills
Languages Common
SQ hard to kill (die @ -20), surge[1d6]
Other Gear 150 GP
--------------------
Special Abilities
--------------------
Hard to Kill (die @ -20) (Ex) Automatically stabilize and die at negative 2x CON score.
Surge[1d6] (Su) You can expend one daily use of mythic power to increase any d20 roll.
Hero Lab® and the Hero Lab logo are Registered Trademarks of LWD Technology, Inc. Free download at
http://www.wolflair.com
Pathfinder® and associated marks and logos are trademarks of Paizo Publishing, LLC®, and are used under license.