So, the short version is, **You Got Lucky**.

Here's the long version:

There are two kinds of reverse engineerable items. The first kind is simple. Reverse Engineer the item, learn the pattern for a slightly better version with a higher color-grade quality, up to **Artifact** grade (Purple).  The chance to learn the higher-quality schematic is usually 20%, you can see the chance when hovering over the item. Most crafted item customizations (Armoring, Barrels, Mods, Enhancements, Crystals, Hilts) and consumables follow this system, as do some craftable weapons (but not most).  A crit on crafting one of these results in two of the item rather than one.

The other system is a bit more complicated. Most *equippable* items, when Reverse Engineered, have a chance to teach you a *variant* of the item, which is upgraded. The new recipes name will have one of three prefixes, based on the additional stat that is added to the item:

- **Redoubt** _______________ items will have increased *Defense Rating*.
- **Critical** ___________________ items will have increased *Critical Rating*.
- **Overkill** __________________ items will have increased *Power*.

Unlike critical crafting with base items, a crit on one of these Prototype items will instead be called **Advanced** when they gain an augment slot.

These prototype items, like customizations, can be RE'd *again*, to give you a chance at an **Artifact** grade item. Once again, there are a number of variants - specifically, for each prefix, there are *five* variants that can be learned. These variant items will have *new* prefixes, and add *two additional stats* to the base item. These items will also have the suffix **[Superior]** unless crafted critically (i.e. with an Augment slot), at which point the suffix is changed to **[Masterwork]**.

### **Overkill** items can be turned into:
 - **Vehemence**, which increases *Power* and *Alacrity*.
 - **Rampart**, which increases *Power* and *Shield Rating*.
 - **Commander's**, which increases *Power* and *Presence*.
 - **Expert**, which increases *Power* and *Surge*.
 - **Hawkeye**, which increases *Power* and *Accuracy*.
  


###  **Critical** items can be turned into:
 - **Leadership**, which increases *Critical Rating* and *Presence*.
 - **Tempest**, which increases *Critical Rating* and *Shield Rating*.
 - **Fervor**, which increases *Critical Rating* and *Accuracy*.
 - **Endowment**, which increases *Critical Rating* and *Surge*.
 - **Supremacy**, which increases *Critical Rating* and *Alacrity*.
  


**Redoubt** items are a bit of a special case. While 4 variants are known, to date, nobody seems to have been able to craft a +Defense, +Alacrity item. Whether this is a bug (people have invested *a lot* of time into researching this), or simply cosmic levels of bad luck is at this date unknown. That said;

### **Redoubt** items can be turned into:
 - **General's**, which offers *Defense Rating* and *Presence*.
 - **Veracity** which increases *Defense Rating* and *Shield Rating*.
 - **Anti-Armor** items have added *Defense* and *Surge*.
 - **Exactitude** will feature improved *Defense* and *Accuracy*.

The image below provides an example of all the variants that can be crafted of one item:

[![Example image][1]][1]


  [1]: https://i.sstatic.net/uLr76.jpg


(H/T to the *incredible* research done by **Slaign** over on the [official forums](http://www.swtor.com/community/showthread.php?t=45866) on this one.)