Is mindfulness for quick enlightenment being exaggerated in the Sutta MN10? I was reading about mindfulness here.  At the end I found this paragraph 


  Let alone seven years, anyone who develops these four kinds of
  mindfulness meditation in this way for six years … five years … four
  years … three years … two years … one year … seven months … six months
  … five months … four months … three months … two months … one month …
  a fortnight … Let alone a fortnight, anyone who develops these four
  kinds of mindfulness meditation in this way for seven days can expect
  one of two results: enlightenment in the present life, or if there’s
  something left over, non-return.


Here Tathagata saying one keeping that kind of mindfulness for 7 days can get enlightenment? Is it exaggeration, translation problem or understanding problem or it's true?
Is it exaggeration, translation problem or understanding problem or
  it's true?


The translation is fine, but the reader must know the environment and situation of that sutta, before read it. If the reader read it without the pre-required knowledge, it is the reader's fail.

The explanation

In atthakathā of MN 10 wrote:


  Why Buddha taught mahāsatipaṭṭhānasutta to Kuru-people? Because they had enough ability to study the advance teaching. It's told that Kuru-people, such as bhikkhu, bhikkhunī, lay men, and lay women,  always had the potential body and the potential mind because Kuru-country had the richness of temperature, etc. Their potential body and potential mind supported their wisdom power, so they can studied  the advance teaching.


So, most Kuru-people were diṭṭhi-cārita, who have little dust in their eyes, according to netti desanāhāravibhaṅga.

The diṭṭhi-cārita people can attain jhāna easily. So they don't have to meditate jhāna because of their pure mind. They can enlighten at the listening moment. That's why in the end of mahāsatipaṭṭhānasutta's atthakathā wrote:


  30,000 people enlightened as arahanta at the end of mahāsatipaṭṭhānasutta was taught.


therefore, the end of mahāsatipaṭṭhānasutta wrote:


  Let alone seven years, anyone who develops these four kinds of mindfulness meditation in this way for six years … five years … four years … three years … two years … one year … seven months … six months … five months … four months … three months … two months … one month … a fortnight … Let alone a fortnight, anyone who develops these four kinds of mindfulness meditation in this way for seven days can expect one of two results: enlightenment in the present life, or if there’s something left over, non-return.


But for taṇhā-carita people,who have much dust in their eyes, they have to meditate jhāna, first. After they attained jhāna, they can count down for enlightenment like what buddha taught in the end of  mahāsatipaṭṭhānasutta. Because jhāna can pause their five hindrances, then their "dust in eyes" state will be same little  dust as diṭṭhi-carita and they are able to count down for enlightenment.