I think we miss this info although we knew about it already.. Will post it anyway.. 

This is from the Official blog of Mafia Wars :

UPATE 2011-04-20 11:40AM PST: We are still working to correct the refresh rate of the new Energy Packs. More information can be found in the Energy Pack Update FAQ.

UPATE 2011-04-19 12:16PM PST: It has been brought to our attention that a number of you are seeing 23 hours as the refresh rate on the new Energy Packs. We are working diligently to correct this issue, and everyone will soon see the new Energy Packs refreshing every 8 hours.

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We at Mafia Wars are committed to making all aspects of your gaming experience more enjoyable and have two exciting developments to announce:

One thing we are working to improve, based on your feedback, is the gift event experience, specifically the amount of time it takes to complete these events. We are excited to announce that the next gifting event will require fewer gifts to be sent and received, while continuing to carry the same type of reward for completion. We hope that reducing the gifting in this event will allow you to spend more time in the game itself, leveling up, icing your enemies, and generally enjoying the dangerous streets in the exciting cities of Mafia Wars.

Mafia Wars is also excited to announce that your feedback has inspired us to replace the Mini 6 Energy Pack with a full Energy Pack sporting the following features:

• 125% refill
• 8 hour refresh
• Use up to 3 per day!

With more energy than you’d get from shotgunning 7 of your favorite energy drinks, you can enhance your strategy, complete more jobs, and level up faster than your enemies, so go out and put these new Energy Packs to work!

We appreciate your patience and feedback while we work to find the right balance to the Mafia Wars experience.

And this is from the 411 page :

Energy Pack Update

Updated 04/22/2011 at 22:07

Energy Packs are a great gift that you can receive from your friends. These extra boosts provide you with the energy to complete more jobs, and level up at a faster pace. Q:  What happended to the Mini-Energy Packs? A:  Due to the feedback from our players, the Mini-Energy Packs have been replaced. Q:  What does the new Energy Pack do? A:  This Energy Pack increases your maximum energy to 125% of your current maximum. Q:  How Many Energy Packs can be used each day? A:  You can receive up to 3 Energy Packs each day. Q:  How long is the timer for the Energy Pack? A:  The Energy Pack has an 8 hour timer. After you use an Energy Pack, you must wait 8 hours until you can use your next one. Q:  What happened if I had not yet used all of my Mini Energy Packs today? A:  Your timer will automatically be reset for the new Energy Pack. If you have any concerns, one of our agents will be happy to assist you. Q:  Why was there such short notice about the change to the Energy Packs? A:  Due to the response we received from the Mini-Energy packs, we felt it best to make the change quickly so that our players could continue with their regular game play. Q:  The timer did not reset for my Energy Pack, what should I do? A:  We are in the process of correcting this for our players.

I know, some people want the mini e-pack back! We like the 6 e-packs but don't want to beg all the time. But Zynga somehow got it wrong.. Now we have the old mini pack with 125% Energy and we STILL have to beg for them...
I say, just take it.. since we can't do a thing.. Just accept our game just the way they are now..